BradS wrote:The shallower decreasing slope at the end of the roast was where I turned off the heat and left the fan running with the variac back at full (130VAC) to see if cooling could be done in situ with any degree of success. You can see - I got impatient and opened the roaster and dumped the beans! There is some more information on the roasting label below, mainly that I decreased the voltage from 110V to 105V to slow down the roast from 1st to 2nd... with fairly good results. I also seem to have a higher-than-normal offset on my temp reading as my temps seem about 40 degrees high compared to visual/audible cues.

I think that, based on the taste of this roast (much less sharp with more body and, well, taste) that I'm on the right track, but It's always nice to have an honest critique. I'd also like to ask other SC/TO users what their best success is with roasting repeatably. I think the variac will help me immensely, as I roast either on the back patio whenever possible or in the garage when necessary due to weather. I get much faster roasts in the garage for whatever reason, maybe either line voltage or ambient conditions, I don't know yet as I haven't used the variac in both places.

In any case, thanks again for all the information you share here.

Cheers,

Brad

Hi, Brad- I've been using an sc/to for almost a year now (I think..), but have never used it without the variac. Unless you've split-wired your turbo-oven (so you can run the fan independently of the heating element) adjusting the variac also adjusts the fan speed. I've tried that early on once I've hit my warm up temp, but found it easier to just leave it turned up full (130 v, in my case) and leave it alone. The biggest trouble I have with consistency has boiled down to two main issues: accurately measuring bean mass temp and achieving good agitation of the beans. My k-type TC and thermometer (the common one people buy from sweetmarias) fluctuates quite drastically when you near 1st crack (upper 300's) and really crazily over 400 (by as much as 25 or 30 deg). Most fluctuation is in the 10 degree range, which is pretty easy to average in your head as you're roasting- but it occasionally dips (not rises) down by as much as 30. I just chalk it up to the nature of that technology (those TC's are not exactly NIST certified). My roasts turn out fine, but my experience with this setup I've likened to pulling shots on a Europiccola (most of the time it's ok, sometimes not so ok, sometimes really great- depending on the bean). I think I can do better, but rather than modding my existing setup, I decided to just buy a decent drum roaster that'll do a good job with up to 1 lb of green.

One other tip I'd offer- maybe roast more than 1/2 lb at a time. I usual roast at least 300 gm, but found it a little easier with 350 in terms of getting an even roast.

Ray

Rainman wrote: My k-type TC and thermometer (the common one people buy from sweetmarias) fluctuates quite drastically when you near 1st crack (upper 300's) and really crazily over 400 (by as much as 25 or 30 deg). Most fluctuation is in the 10 degree range, which is pretty easy to average in your head as you're roasting- but it occasionally dips (not rises) down by as much as 30. I just chalk it up to the nature of that technology (those TC's are not exactly NIST certified).

Ray

I don't know about those particular TCs you reference, however even the cheap ones are fairly accurate in my experience. The probe I mounted permanently in my sample roaster was custom made for me by Omega, and I'm sure it is of very good quality and especially with the Fluke digital thermometer/datalogger I have it attached to, gives highly accurate and repeatable results. By the way, Omega is a great company to work with and they will talk with you on the phone to help you design a custom probe which they will then fabricate for you in less than 2 weeks. If my memory is correct, I paid about $60, 2 years ago, for this probe which is ensheathed in stainless steel and has heat insulation and is flexible at the far end.

Nonetheless, even a cheap digital thermometer that costs <$20, including the TC, will be accurate in my experience. The differences I've measured with a cheap TC on a cheap digital thermometer, vs. an expensive TC attached to my Fluke, are on the order of 1-2 degrees, and neither the cheap nor the expensive TC fluctuate much, they just read differently.

I have one of those IR TC things that looks like a pistol, that you can use to sample temperatures. In my experience, using it for roasting and getting temps from inside my roasting drum, you can get almost any temperature you want depending on where you aim the thing. I would not be able to depend on such a device for roasting coffee; it would give me very little additional information than simply looking at the beans as they roast.

ken

Abdon wrote:I think (therefore I could be horribly wrong) that messing with the temperature before a good roaring 1st crack is dicey at best.

I agree but I also agree with Ken with regards to the kind of roaster/roasting method you're using. They're all different and I would imagine even between the same electric home roasters they vary with regards to one's line voltage, ambient temperature and even altitude above sea level.

I find anticipating my Hottop is a bit like trying to turn a big rig...you've got to set up in advance. If I keep the heat high during 1st crack and only ease off 1/2 way or more into it the chamber temp responds very slowly and I'll go from 1st crack temp to 2nd crack very quickly, leaving me with a pretty short rest. Atleast for my Hottop it looks like backing off on the heat at the start of 1st crack would probably level off the temp towards the end where I'll have more of a chance to control the rest into 2nd.

Aside from the direct drum heat the Hottop has a programmable fan to allow for convection control as well. What's the benefit of the fan/convectional heat and at what stage is it best used for the roast? Setting up for first, through first or throughout the roast?

Ken Fox wrote:I don't know about those particular TCs you reference, however even the cheap ones are fairly accurate in my experience. The probe I mounted permanently in my sample roaster was custom made for me by Omega, and I'm sure it is of very good quality and especially with the Fluke digital thermometer/datalogger I have it attached to, gives highly accurate and repeatable results. By the way, Omega is a great company to work with and they will talk with you on the phone to help you design a custom probe which they will then fabricate for you in less than 2 weeks. If my memory is correct, I paid about $60, 2 years ago, for this probe which is ensheathed in stainless steel and has heat insulation and is flexible at the far end.

Nonetheless, even a cheap digital thermometer that costs <$20, including the TC, will be accurate in my experience. The differences I've measured with a cheap TC on a cheap digital thermometer, vs. an expensive TC attached to my Fluke, are on the order of 1-2 degrees, and neither the cheap nor the expensive TC fluctuate much, they just read differently.

I have one of those IR TC things that looks like a pistol, that you can use to sample temperatures. In my experience, using it for roasting and getting temps from inside my roasting drum, you can get almost any temperature you want depending on where you aim the thing. I would not be able to depend on such a device for roasting coffee; it would give me very little additional information than simply looking at the beans as they roast.

ken

It's possible that the placement could be the issue. The tip is protruding out from the bottom near the center, and some of the cloth sheathe may be stripped back far enough below the pan to affect it's reading somewhat. The readings are very stable up to around 350 deg F, then as they climb toward the upper 300's, start to fluctuate more (realizing fluctuation of readings and accuracy are different issues, of course). I could have sworn that somewhere (maybe over on the greencoffeebuyingclub forum from someone like Greg Anderson (aka "buttwhiskers") mentioned the accuracy of these units varying substantially at higher temps... yes/no? You sure, Ken? Either way, I'll have a chance to compare it w/ the TC that comes w/ my new roaster if I can figure out a way to match it's placement w/ the cheaper probe.

Ray

Ken,
It seems to me you are advocating an 8 minute 1st crack with another 4 minutes from that point until the roast is finished. That is a total of 12 minutes roasting time which in my opinion is to quick for almost any coffee except maybe shb fully washed and fermented.

My preferred roast usually end up at an 11 minute fist crack dropping the gas to low 30 seconds before first crack. With a total time with the gas on low of 2 minutes and 30 seconds. Then slowly bumping the gas up every 30 seconds until it is medium high finishing the roast at 16 minutes. That leaves a total time of 5 minutes in between the the start of first crack to the finish of the roast right before second crack for me as well.

This seems to work fine.
I have known several professional roasters who even prefer there first crack at 12 minutes start and 5 minutes from the beginning of first crack. That would make the total roast time about 17 minutes.

Slower profiles work better for dry processed coffees as there moisture content is all ready low and easy to scorch.

I prefer to drop by gas to low 30 seconds before 1st crack right before the beans to exothermic so bean temperature keeps going up on its on with minimal gas and the roast does not get out of control.

My question for you Ken is have you tried expanding the gap between 1st crack and the finish of your roast to five minutes and compared it to a roast finishing at the same time where the gap between 1st and second is only 4 minutes.

I would be curious to know your opinion of those coffees.
I realize that gap between the start of 1st crack and the finish of the roast is the most crucial to the whole roasting process. To long a stretch brings baked results to short brings coffees that have flavors that are undeveloped that may be bright and thin and missing body.

I have good results they way I roast coffee. But i did the experiment you suggested my 1st crack at 830 the finish of my roast at 1230 the coffee came out a little darker than it usually is for me.

I am going to cup the coffee a dry processed brazil and let you know what I think.

Thanks,
Anyone else with some opinions feel free to chime in.
This in itself to me is a great topic.

jason_casale wrote:Ken,
It seems to me you are advocating an 8 minute 1st crack with another 4 minutes from that point until the roast is finished. That is a total of 12 minutes roasting time which in my opinion is to quick for almost any coffee except maybe shb fully washed and fermented.

My question for you Ken is have you tried expanding the gap between 1st crack and the finish of your roast to five minutes and compared it to a roast finishing at the same time where the gap between 1st and second is only 4 minutes.

I would be curious to know your opinion of those coffees.
I realize that gap between the start of 1st crack and the finish of the roast is the most crucial to the whole roasting process. To long a stretch brings baked results to short brings coffees that have flavors that are undeveloped that may be bright and thin and missing body.

I have good results they way I roast coffee. But i did the experiment you suggested my 1st crack at 830 the finish of my roast at 1230 the coffee came out a little darker than it usually is for me.

I am going to cup the coffee a dry processed brazil and let you know what I think.

Thanks,
Anyone else with some opinions feel free to chime in.
This in itself to me is a great topic.

Hi Jason,

Actually, I did not recommend any particular profile to other users, especially people with different equipment than mine. At the end of my first post I did state what I have found, at this point, to work the best with my equipment, but it was intended simply to illustrate an approach that had developed on the basis of my own study of the results in my own roaster, over a period of years. Here is what I stated at the start of the post, which was the "meat" of what I was trying to get across:

Ken Fox wrote:Here is a description of the roasting parameters that work best in my equipment and may or may not work well in yours. Even if my parameters don't work for you, knowing that these parameters exist may help you to experiment a bit with altering them in order to find what works best for you. I have a drum and therefore if you air roast you will need to extrapolate to your particular set up, as the processes are different even if the results can be similar.

In answer to your question, there was a period of time during which I did not even have a strong enough heat source to roast as quickly as I now roast, whatever I might have wanted to do. After I changed the heat source (the burner) to something more powerful, and later adjusted to a change of fuel from propane to natural gas, I still roasted much longer profiles than I now use, averaging about 16 minutes (sometimes 18 minutes) in total to a bit darker roast level, although the difference in roast level isn't anything approaching the ~4 minute difference in roast times. I used to routinely hit first crack after 10 or even 11 minutes, and had years when I roasted like this.

My experience with my particular roaster, which is probably not similar to most peoples' roasters, was that roasts that took 10 or 11 minutes to hit first crack invariably tasted "flat" or "dull." I had several people whose tastes I respect tell me that when I sent them samples of my roasts, and it was suggested to me by more than one of these people to speed up the time to the onset of 1st.

Each roaster has its own best profiles, which are probably going to differ a bit by bean but the overall average profile for any given roaster is probably going to be fairly similar, at least in my experience.

As to extending the time from onset 1st to the termination of the roast, I think this is going to depend in part on how dark you are roasting. I am able to reliably get 4 minutes in between the onset of 1st and where I terminate the roast, typically several degrees before the onset of 2nd. Could I get 5 minutes in there? Maybe, but I think the risk of stalling out would be higher and I'd really have to stand in front of the roaster every second to try to avoid that. I might try it, but I'm not sure I really want to go in that direction as it would be a real PITA, especially if I stall out and then have to dispose of the coffee on some unsuspecting friend

ken

Ken,
Thanks for the reply.
As we have been peers and colleague's in espresso since alt.coffee.
I figured I could ask candid questions without taking them the wrong way.
I myself am never locked into a formula for anything so I wanted to try your methodology to see if it gave me better results with my own roaster.

As to getting 5 minutes in between 1st crack to the finish.
I start my timing cycle when I drop the temp 30 seconds before 1st crack and include that with my timing that is how I am getting 2 minutes and 30 seconds on low. Then I slowly increase the temp every 30 seconds until it is medium high.
By that point I usually have about 1 minute and 30 seconds to until the roast is finished. This is how I am able to achieve that 5 minute span with repeatable accuracy.

I am wondering what your current final finishing roast times are.
12to 13 minutes I am guessing.

As far as roasting we are not locked into a system we all have to find what works optimal for us.
Good for you for doing that.

I cupped my Brazil roasted in the profile you are using and it cam out less than optimal for me.
My roaster out a nutty brazil but finished roasty ashy and bitter a bit.

Oh well I will roast some brazil today at my optimal roast times and compare it to the brazil I roasted with your profile.

Learning is sure fun.

Best Regards

jason_casale wrote:Ken,

I myself am never locked into a formula for anything so I wanted to try your methodology to see if it gave me better results with my own roaster.

As to getting 5 minutes in between 1st crack to the finish.
I start my timing cycle when I drop the temp 30 seconds before 1st crack and include that with my timing that is how I am getting 2 minutes and 30 seconds on low. Then I slowly increase the temp every 30 seconds until it is medium high.
By that point I usually have about 1 minute and 30 seconds to until the roast is finished. This is how I am able to achieve that 5 minute span with repeatable accuracy.

I am wondering what your current final finishing roast times are.
12to 13 minutes I am guessing.

As far as roasting we are not locked into a system we all have to find what works optimal for us.
Good for you for doing that.
Learning is sure fun.

Best Regards

My typical roast times these days are around 12 minutes.

I don't think that a profile that works with a certain roaster will necessarily work with others; you have to play around with them. And it is completely possible that two years from now we will both be roasting differently. The key is to taste what you have roasted and to make changes as needed. I just roasted a new Kenyan a few days ago and so far I don't like it very much the way I roasted it, however I did have some problems keeping the temperature from stalling after the onset of 1st crack, so perhaps I just need to give those beans more heat the next time around.

My current finishing roast temps are about 435F, making allowances for the fact that my TC probe reads hotter than reality.

Take care and good luck!

ken

You know just doing some quick research in sample roasters.
It seems they cant line up with regular drum roasters profiles.
in other words they will not profile the same.
I saw some online saying they actually profile faster.
That would agree with your overall results.
I think both have had good experiences learning to roast on our equipment
over the past couple of years.

One thing is for sure you certainly learn the most about roasting using 100 percent manual equipment is a great teacher.
I have learned more about roasting than I would have using a computer aided roaster.
The down side you have to constantly monitor your roast and you are always making changes as you move along.

Gas fired roasting is a beautiful thing we have so much more control over the roast than when we home roasted.
Now having that experience I am not sure I could ever go back to a home roaster.

No offense to home roasters as you people get amazing results often times out of those little roasters.

I wish you the best out of your roasting.

jason_casale wrote:You know just doing some quick research in sample roasters.
It seems they cant line up with regular drum roasters profiles.
in other words they will not profile the same.
I saw some online saying they actually profile faster.
That would agree with your overall results.

One thing is for sure you certainly learn the most about roasting using 100 percent manual equipment is a great teacher.

The down side you have to constantly monitor your roast and you are always making changes as you move along.

Gas fired roasting is a beautiful thing we have so much more control over the roast than when we home roasted.
Now having that experience I am not sure I could ever go back to a home roaster.

I wouldn't admit this if I didn't know that you could keep a secret

There was a time when I used to approach home roasting as a chore, and would find other things to do when I roasted, such things as waxing my skis across from the roaster, in the garage.

That definitely impacted my results, and not for the better!

ken

Rainman wrote:Hi, Brad- I've been using an sc/to for almost a year now (I think..), but have never used it without the variac. Unless you've split-wired your turbo-oven (so you can run the fan independently of the heating element) adjusting the variac also adjusts the fan speed. I've tried that early on once I've hit my warm up temp, but found it easier to just leave it turned up full (130 v, in my case) and leave it alone. The biggest trouble I have with consistency has boiled down to two main issues: accurately measuring bean mass temp and achieving good agitation of the beans. My k-type TC and thermometer (the common one people buy from sweetmarias) fluctuates quite drastically when you near 1st crack (upper 300's) and really crazily over 400 (by as much as 25 or 30 deg). Most fluctuation is in the 10 degree range, which is pretty easy to average in your head as you're roasting- but it occasionally dips (not rises) down by as much as 30. I just chalk it up to the nature of that technology (those TC's are not exactly NIST certified). My roasts turn out fine, but my experience with this setup I've likened to pulling shots on a Europiccola (most of the time it's ok, sometimes not so ok, sometimes really great- depending on the bean). I think I can do better, but rather than modding my existing setup, I decided to just buy a decent drum roaster that'll do a good job with up to 1 lb of green.

Just curious - is your probe sticking into the bean mass where they can collide with it? I think that would account for the fluctuations. I tried that early on, but found that a steady reading (with the proble just above the beans)with a known offset based on visual observation is much easier to use.

Rainman wrote:One other tip I'd offer- maybe roast more than 1/2 lb at a time. I usual roast at least 300 gm, but found it a little easier with 350 in terms of getting an even roast.
Ray

Good point. I have every intention of doing that eventually, but I wanted to leave the batch size variable alone until I mastered roasting 1/2lb batches. I'm close, but I still think that I could improve somewhat.

BradS wrote:Just curious - is your probe sticking into the bean mass where they can collide with it? I think that would account for the fluctuations. I tried that early on, but found that a steady reading (with the proble just above the beans)with a known offset based on visual observation is much easier to use.

Yes- it comes up through a hole I drilled near the center opening in the pan where the spindle comes up out from the bottom, and is always buried in beans (I roast enough to be sure of that). That was a suggestion I found, I think on coffeegeek. I think I've found the problem (shoulda checked on this earlier)-- the cloth shield around the probe has worn back a bit below the hole where it comes up out of the pan, and I think I'll just replace the entire probe (they're fairly cheap, anyway)... just gotta get around to it.

Ray

Hello Ken,

I've been taking some of your experiences and experimenting with their application to my set-up. While not a commercial sample roaster with advanced thermometry I do feel comfortable with what I roast with and do enjoy the results.

Sure there are differences between our roasters that require a change in profiling but I'm surprised at how much change I've seen striding for the times you go for. This morning I am pulling Sweet Maria's Liquid Amber espresso blend and it's the best batch I've had for some time. I must admit my roasts for the past month or two have been leaving me unsatisfied. I had been roasting longer/slower(bigger/too big batches). The coffee was always just blah with a terrible hint of green vegetable. I knew something was wrong.

I adjusted my Anita to 9-bar (blind basket) and that helped but the coffee was still missing something. After some conversations with Jim Schulman and some of his posts I began to wrap my mind around the importance of pre-first crack. Before I didn't worry about it. Now I find that less than nine minutes here (again on my set-up) is best and surprisingly a brisk 3-4 minute run to the end of roast also works nicely for accentuating the chocolate and earth notes. Most notably though is this coffees brightness has returned. It's no longer dull and mediocre but now I can taste the different flavor notes and the body is still quite good.

I didn't intend to be this longwinded so I'll wrap it up just wanted to say thanks for sharing your observations. Its discussions like these that make me evaluate my own methods and most often times cause me to make the next step in quality. It took you years of your own experimentation/experience to figure these out, thanks to your generous sharing I won't have to endure that. I much appreciate it!

TimEggers wrote:Hello Ken,

I've been taking some of your experiences and experimenting with their application to my set-up. While not a commercial sample roaster with advanced thermometry I do feel comfortable with what I roast with and do enjoy the results.

I didn't intend to be this longwinded so I'll wrap it up just wanted to say thanks for sharing your observations. Its discussions like these that make me evaluate my own methods and most often times cause me to make the next step in quality. It took you years of your own experimentation/experience to figure these out, thanks to your generous sharing I won't have to endure that. I much appreciate it!

Hi Tim,

I'd hate to give you the idea that I've "figured all of this out." Like you, I have sought out other peoples' opinions and have tried their suggestions. Some have worked in my setup and some have not. But it is a continual learning game. Right now I have a Kenyan that Jim Schulman recommended to me a few months ago that I have yet to get what I would call a satisfactory roast out of; they were drinkable, but certainly not "special" in any way that would justify buying them. I have a couple of more things to try on that coffee, which in contrast to most of what I buy is a wet processed bean rather than a dry one. I think I'll finally get good or even great results out of that coffee but it is going to take at least three separate tries (counting the next one, hopefully late this afternoon) to accomplish that. The key is to taste what you produce and not to tell yourself it is the best coffee around because, after all, you roasted it

I don't think I could ever be satisfied with a roasting setup that did not allow me near absolute control over the roast profile. There is no way that the manufacturer of a roaster aimed at the general public is going to anticipate the way that all the different coffees out there will roast. It is going to take trial and error to find the best profiles for the coffees you like to roast. Without control over the process your results are going to be mediocre, at least for those who are objective enough to notice.

ken

Hello Ken,

First no I don't get the impression "that you have it all figured out" I do however recognize your experience and like you collect and experiment on the experiences of others. Again thanks for sharing some tips they seem to have translated quit well to my set-up.

Currently I am on day four of the batch above (Sweet Maria's Liquid Amber espresso Blend) and its much better then previous batches I've done. First and most noticeably it tastes exactly like it smells...monsooned blueberries (and I mean blueberries)! Wow it's amazing. Its also quite balanced more so than before. Previously I would get more bas note than anything without much on the upper end. This batch seems more balanced and maybe even a tad towards the fruit more so than the earth and sadly very little chocolate.

Sadly I don't have the setup/time/circumstances for too much formal cupping (I don't have the palate for that anyways) but this batch seems night and day different then previous batches of this. I've been using Liquid Amber since my beginnings of home espresso and this last batch is the one that finally "feels right" so to speak. The crema is very sweet and a joy to experience (a true first for me). Overall an earthy smoky blueberry shot and damn good straight up.

Another observation this stuff pours like magic. An indication of a roasts affect on the beans physical structure? I can't explain it but this stuff comes on thick and pours evenly forever (Jon Rosenthal would be proud) no matter how I dose or distribute it. I've not seen this blend (or any blend home roasted so far) be so forgiving and damn tasty.

I'm glad you took the time to share as you have; it has helped my espresso immensely. Thank you!

Hi Tim,

So now is the time to start experimenting with single origins! I haven't roasted a blend other than the simple 75% Ismaili/25% aged Sumatra Lintong (both former green bean coop coffee offerings) in some time. A good single origin will really open up your eyes to some of the particular flavors that come from specific beans from specific origins. If you choose them well, and roast lightly, many are very good for espresso when dosed at the lower, Italian-ish part of the range (e.g. around 14g).

Continue to experiment; it is what makes all of this interesting!

ken

I'm going to quote myself from another thread (which was concerning the Behmor roaster) to make a point that was once again proven to me, and very recently (like yesterday). Here's the quote:

Ken Fox wrote:
My general opinion of home roasters' evaluations of their own roast products, however, stands. This extends to my own opinion of my own roast results. I regularly send out samples to people whose taste I respect, in order to seek feedback and be sure that I am being objective on this subject regarding my own results.

ken

My own roasting practice has changed a lot the last 6 months or so, following a visit from Jim Schulman during which we had a chance to compare some roasts I had made with differing intervals between the onset of 1st crack and the end of the roast. What I found at that time was that periods of only 2.5 minutes between the cracks produced flat tasting coffee, whereas longer intervals had much better results.

Since Jim's visit I've been toying around with this and adjusting roast parameters to try to get this longer interval. My experimentation with this reached a zenith over the last couple of months since I came back from a month in France. I have done 3 or 4 roasts during this period, the last of which was a week ago. Fortuitously, I sent out some samples from the last roast and have just received some feedback, which was not especially good but which I think was right on the mark, that the coffee was over roasted.

There were obvious signs of this which I had noticed but had failed to pay attention to; by day 3 my beans had much more evidence of oil spotting and were darker than before I'd changed the roast profiles. In addition, there was the audible start of 2nd crack several degrees before I dumped the beans, but I'd convinced myself that I was imagining it. My real-time thermometry indicated I was dumping the beans at least 6 degrees F COOLER than before, which convinced me that they were lighter when in fact they were DARKER.

How did this happen? I have, afterall, more than 4 years experience with this roaster and I have installed a custom made ensheathed thermocouple in the drum, which allows me to follow the temperature in that part of the drum, in real time:



The TC is inside the drum but just above the roaster's burner. With my previous roasting profiles, I was applying a lot more heat at the end of the roasts and as a result, the beans were not as hot as the radiated heat reaching the probe would have indicated. As a result, I had a "mental offset" that I used, a correction as it were, of minus 14 degrees F that I would use when following the roasts on my Fluke digital thermometer. So, if it read 440F, that "meant" 426F to me in "real degrees."

In my recent roast sessions, where I was intentionally prolonging the interval between the onset of first crack and the end of the roasts, the flame height was hugely lower, which was the only way I could slow down the roast in this roaster. Since I was now adding very much less heat, the height of the flame and the heat it radiated into the drum was much less important. As a result, my "mental offset" of 14 degrees F was no longer valid. In fact, it might well be that most or all of this offset was no longer needed and the temperatures I was viewing on the Fluke were (perhaps) correct (or close to correct) bean mass temps. The result was that I was taking the roast to higher actual temperatures than I had intended, because I failed to realize that by changing the method of roasting, I had effected the validity of the thermometry I was using to guide the roasts.

My point in posting this is threefold;

(1) When you change aspects of how you roast, you may change other characteristics as well (in this case it was how one should interpret the thermometry, with the result being that the same numbers can mean different things depending on the measurement system and its limitations);

(2) Use all the information you have available. There was ample evidence that the roast levels had changed, everything from the appearance of the beans days later to the auditory 2nd crack, which I paid no attention to because I thought I had a "superior" measurement, in this case the thermometry, which it turns out needed to be interpreted differently. Use all the information you have and don't disregard any of it;

(3) It really pays to have others taste your results. None of us are professional roasters and it is folly to think that we can really judge our own roasts objectively. This is why, when I read posts from home roasters extolling their roasts, that I tend to take a jaundiced view. Rather than thinking you are a great roaster, it is more correct to think of yourself as someone who can do a good job roasting, but can also do a poor one. You are not really like a chef, but more rather like a cook. A cook can have good results, but he is not a pro like a chef. Unless you do a hell of a lot more roasting than your typical home roaster, it is very unlikely that you will ever get to the point where your roast products will be as reliably good as someone who not only has training in this, but who does this day in, day out, as a job. I've learned for myself, previously, that if I can nail a profile and then repeat it over and over, reliably, that I can have consistently good results. When I tinker with the profiles, when I am in a period where I'm revising them, the results are going to change and it pays to solicit the opinions of others before letting these changes become permanent.

I have learned that lots of small incremental changes in roasting parameters can add up to big changes in the results, and these changes are not always going to be for the better. It is easy to fool yourself in the process and to lose sight of the big picture, of even obvious things like roast level that you really should not overlook. I am going back to the "drawing board" with this experience and am going to try to take the best things I've learned in my time with my equipment, and to come up with a new profile that will more effortlessly (and reliably) incorporate the things I want in my roast profiles while avoiding those things I want to avoid. In the long run I think this will be more effective than simply trying to cut the roast level by dumping the beans earlier with my most recent profiles.

ken

Ken and all: Nice posts. With the introductions of so many electronic preset home roasters now on the market roasting forum chats have changed much. I have been going in the opposite direction by designing and building a home roaster with the maximum amount of controls, adjustment capabilities and monitoring abilities. As you mention as home roasters we just don't get the experience from roasting many batches as one would in a commercial situation. Good monitoring equipment and design are important for us. I use 2 thermocouples, one for environmental temp and 1 for bean mass. temp. I also use a variac with a "kill A Watt" meter to know, adjust and record my voltage and effects. I spent the past 2 years tweaking my machine designs and have for the past few months begun to experiment with different adjustments. With my roaster I also have the ability to adjust the % of conduction and convection used. I'm not yet ready to say what is wrong or what is right but I will say that adjustment and monitoring are extremely valuable in the learning process. An accurate bean mass temp. reading was one of my major focus. I didn't want it to be diluted from accuracy by changes in environmental or conduction heat changes. I'm glad to see that some home roasters have upgraded to sample roasters rather than going preset. Keep this thread Alive! A pic of my roaster.
ps the PID/timer is not yet hooked into my system. In the future I may add it for repeating roasts along with a motor drive on the variac.

Ken Fox wrote:None of us are professional roasters and it is folly to think that we can really judge our own roasts objectively. This is why, when I read posts from home roasters extolling their roasts, that I tend to take a jaundiced view. Rather than thinking you are a great roaster, it is more correct to think of yourself as someone who can do a good job roasting, but can also do a poor one. You are not really like a chef, but more rather like a cook. A cook can have good results, but he is not a pro like a chef. Unless you do a hell of a lot more roasting than your typical home roaster, it is very unlikely that you will ever get to the point where your roast products will be as reliably good as someone who not only has training in this, but who does this day in, day out, as a job.

ken

Please speak for yourself on this point.

I have read many of your post, some I learned from, some I agreed with and some I disagreed, but with some of the conclusions you made in point 3, with all due respect, I say hogwash! You are one that has a mindset that a "Professional" will outperform or get results superior to an amateur. This is often, so far from the truth. A professional will almost always be able to produce better "productive" results but it is the serious committed hobbyist, for the love of what they are doing, that very often produces better quality results. I'm not just talking roasting here.

I have seen this consistently in the Trades & Crafts. Woodworking is a good example, where the lone artisan in his garage workshop, will spend the time, commitment and love into his work to produce a real work of art; that not many "professionals" in production could ever produce; nor could they feasibly produce to make a profit. I have dined in dozens of restaurants on the scale from grease-pit to elite, and everywhere in between. I have seen Chefs that can manage their kitchen so well that they can produce twice the output with half the normally required staff. I have seen some that can work with color and put out a gorgeous presentation that is truly a work of visual art; but to say things like "A cook can have good results, but he is not a pro like a chef" implying that a chef will constantly get better results than a committed home cook, is again hogwash.
There are so many devoted coffee hobbyist now, that seriously experiment with many different beans, roast profiles, and blends, more so than many "professionals" do; and to say that a home roaster cannot produce results reliably good as a professional, not only imho is untrue, but an unjustified slap in the cooling tray to those who are really committed to the craft.

Part of producing excellence, is a love and commitment to what you are doing; that gives one the drive to achieve that excellence. You stated several instances, that at one time you considered roasting a PITA, perhaps subconsciously you still consider roasting a PITA, maybe your going through the mechanical motions of commitment, but in reality, it's not your heart, thus not getting the results your happy with.

Again, I respect your knowledge, and commitment to coffee. However, the problem is, many may take your opinions as gospel, and in this case, I believe it can negatively impact and discourage those susceptible, and those just getting into the hobby. I got into home-roasting because a local professional micro roaster could not give me consistent product, I finally got tired of it. The hit or miss quality of their product was the best thing that happened to me, It got me into my home-roasting hobby. I will never look back.

In a nutshell, I'm just saying:
Being a professional, does not always mean you're producing excellence ; and the lowly home roasting aficionado can produce some pretty damn good stuff, stuff that at times, can even make a pro envious. (that goes for some of you "home chefs" as well)

Reality Check