Behmor - Optimizing 1/4 Pound Roasts - Page 2

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
DavidZ

#11: Post by DavidZ »

babalu120483 wrote:- 1C was at 10:30 with a B temp of 237
- I will check tomorrow when I run another batch but the first time I ran the behmor my voltage was pretty stable
- Unfortunately I did not follow this step and left it inside with the door open.

Tomorrow I will follow the protocol to a T and will report back.
Something doesn't sound right to me. I consistently get to 1C at about 7:30 to 8:00 with a B temp of about 260 to 270.

I found that my line voltage was consistently between 120 and 121 when I started roasting in March. But when spring came and people started using their air conditioners, the voltage dropped to as low as 116. When I ran the Behmor, it could drop as low as 112 or so. That's when I bought a Variac. According to the Behmor literature, you don't want the voltage to drop much below 116 with the Behmor running. You can't just test your line today and think it's good going forward. You have to test your line at the time when you're roasting.

Also, make sure you're following the protocol carefully as outlined in the first post above. It's a complicated little dance on the Behmor keyboard. I've done about 20 roasts so far with it and I still have a hard time getting it right. I mess it up about one-third of the time. My most common mistake is to forget to hit P4 right after hitting Start at the beginning of the roast. That mistake could produce the results you're getting.

maccompatible

#12: Post by maccompatible »

Your roast technique is pretty similar to mine, but I'm even more aggressive to get the Behmor to roast hotter when needed, which is most of the time since my preferred coffees are high grown Central American coffees. I'll quote and edit so you can see what we do differently.
DavidZ wrote:1. Load the drum with beans. Insert the chaff tray but keep the drum out. Preheat to 325 degrees by pressing 1, Start, P5. It usually takes about 6 minutes. Quickly remove the chaff tray, insert the loaded drum, and replace the chaff tray.
2. For 155 grams of beans, press 1/2, Start, P5. This places the machine at 100% power in manual mode.
3. When the machine recovers back up to 325, lower to P4 to avoid the Err7 code, at which point the Behmor thinks it's too hot and turns itself off.
4. At 7:00 on the countdown timer (5:00 into the roast), press P5 (this offsets the affect of the afterburner, which comes on at 5:00 with these settings)
5. At 5:50 on the countdown timer (after 70 seconds), press P4
6. When first crack beings to accelerate, usually at or before 7 minutes, or 5 minutes on the countdown timer, press P3
7. Depending on the roast trajectory I'm looking for, I may continue reducing the heat to allow longer development time while monitoring A temperature to make sure the roast doesn't stall. Anything Full City or above I leave on P3, but for lighter roasts I usually reduce to P2 midway through first crack.
8. At 12:00 * 0.25 = 3, press Start to prevent the Behmor from helpfully shutting off and ruining your beans! My roasts are usually done at this point, though.
9. Press Stop when the roast is at the desired point. Wearing gloves, quickly remove the chaff tray, remove the drum, and press Cool to start the cooling cycle. Immediately begin the cooling procedure. Cool beans in as close to 4 minutes as possible.
A lot of the differences between our techniques is likely just because of my bigger charge of 155g vs your 113-ish grams, and it looks like most of the heat and time management follows similar principles. I do handle things differently with dry processed coffees (P4 instead of P5 during the drying phase) but otherwise this is what I do every single time. I've been really happy with it, and it's neat to see someone else figuring out something so similar that works for them too.

One quirk I have noticed, though, is that you only have about 2 minutes of useful temperature readings on the Behmor. B temperature is basically useless for me since it should always be high due to the preheat. And A temp, which is supposed to be the best correlation to bean temperature, only turns on with the fans at the 5 minute mark, and I don't trust it for at least the first minute (see below. There's no WAY my RoR is changing that much). I also don't trust it after first crack ends. On the rare event I take my beans into second crack, the A temperature actually drops, which would be expected of the environmental temperature in a drum roaster. So I'm really not sure where the "A temp correlates to bean temp" idea came from.

Anyway, here's a manually drawn graph of a typical roast on my Behmor.
The Blue line represents A temperature, and is graphed with the black numbers on the left.
The gray line is what I believe the bean temperature likely is, based on the average temperature that these stages happen (drying ending, first crack beginning and ending, second crack, etc). I drew it so that it lined up well with the blue once I began to trust what "A" told me.
I didn't draw the RoR curve, but I wrote the values in purple beneath the curve. This calculation was based on A temperature readings, not the estimated true temperature (gray).
The red lines are where things happened (drying end, first crack, first crack ending), and the green lines are when I made temperature adjustments.
I actually dropped this roast at 8:45, so the blue and gray line continuing from there is just to show what WOULD happen in a darker roast: the bean temp MUST be going up or else second crack wouldn't happen, but A temp actually goes down. So I estimated using the top heavy blue lines as being the range that A temperature is actually useful.
Image

SO at the end of the day, this technique works pretty well, but it's all about evaluating the roast and tweaking the next based on the results, instead of using hard-fast data DURING the roast to decide what to do like those with data-logging drum roasters can do. It can be a bit of a hassle, but I don't often have unpleasant results using this method.
"Wait. People drink coffee just for the caffeine??"
LMWDP #628

DavidZ

#13: Post by DavidZ »

maccompatible wrote:Your roast technique is pretty similar to mine...A lot of the differences between our techniques is likely just because of my bigger charge of 155g vs your 113-ish grams, and it looks like most of the heat and time management follows similar principles.
Awesome! I couldn't agree more. It's great to have a fellow traveler down this road. I'm optimizing 1/4 pound roasts and you're optimizing 1/3 pound roasts.
I do handle things differently with dry processed coffees (P4 instead of P5 during the drying phase) but otherwise this is what I do every single time.
What do you do with P4 and P5 coffees? I've done some experimenting, but my results are mixed and don't point to any conclusions for me.
I'm even more aggressive to get the Behmor to roast hotter when needed, which is most of the time since my preferred coffees are high grown Central American coffees.
I've tried this, too, but with minimal success. What are you doing and what are your results?

maccompatible

#14: Post by maccompatible »

DavidZ wrote:What do you do with P4 and P5 coffees? I've done some experimenting, but my results are mixed and don't point to any conclusions for me.
Basically my thought process is this: DP coffees are often lower density, and do better taking on heat more slowly. If I preheat to 325 and load in the drum, the temp drops different amounts depending on my setting. For washed coffees I do like I said and use P5. With that, the B temp drops to about 315 and usually gets back up to 325 by two minutes. To avoid overheating, I turn it back down to P4 and hold at max heat (325-327) until the fans kick on, at which point I can turn the heat back up to P5.
BUT, with DP coffee I only have it on P4 after loading. This allows the heat to fall closer to 300, and it usually doesn't get back up to max temp before the fans. I still turn it back up to P5 at the 5 minute mark for a couple minutes to offset the afterburner effect, and to avoid the roast going too long. With my batch size, using these settings, the drying phase gets lengthened by about a minute (which definitely helps the flavor be sweeter/more syrupy) and makes the whole roast about a minute longer overall. I do the same heat reductions once I get to first crack, though.
DavidZ wrote:I've tried this, too, but with minimal success. What are you doing and what are your results?
Basically my whole method I outlined above is me being as aggressive as possible, except for beans that need less heat (DP, honey process, etc). Higher preheats, higher heat settings when possible, faster drum speeds, etc. I'm MUCH happier with roasting a third pound in 8-9 minutes compared to the 12-13 with stock settings.
"Wait. People drink coffee just for the caffeine??"
LMWDP #628

DavidZ

#15: Post by DavidZ »

Thanks, Matthew. You've given me a lot of good food for thought. I'm definitely going to try preheating to a higher temperature.

I've been roasting with the procedure posted at the beginning of this thread for about 2 months now. The roasts have been consistently great over a wide variety of coffee beans including beans from Columbia, Peru, Papua New Guinea, Guatemala, Costa Rica and Burundi. Note that the Papua New Guinea and Burundi are dry process coffees. Roastmasters recommends the Behmor P3 profile for the Burundi and P2 or P3 for the Papua New Guinea.

I tried some variations from this protocol. The only variation that significantly improves the roast is to cover the chaff tray with aluminum foil for the P1 coffees (Columbia, Peru, Guatemala). The aluminum foil reduced the time to first crack by about 30 seconds (from about 7:45 to about 7:15). The result is a much fuller and more flavorful roast.

brianl

#16: Post by brianl »

Have you seen the various behmor roasts on the sweet maria's blog? For instance @https://legacy.sweetmarias.com/library/ ... operative/

I guess the only real question I had is when you said your FC hits around the 270F number. It's interesting that you charge very hot but you temperature doesn't appear to really go into the 300Fs.

I need a bit more coffee so i'm around 200g so i'll have to see what changes need to be made, if any. how much rest do you typically give your beans?

DavidZ

#17: Post by DavidZ »

brianl wrote:Have you seen the various behmor roasts on the sweet maria's blog? For instance @https://legacy.sweetmarias.com/library/ ... operative/
No, I haven't. I suggest you try both approaches and decide for yourself.
I guess the only real question I had is when you said your FC hits around the 270F number. It's interesting that you charge very hot but you temperature doesn't appear to really go into the 300Fs.
Keep in mind that the Behmor B temp is not bean temp. It's the temp of the wall inside the roaster.
I need a bit more coffee so i'm around 200g so i'll have to see what changes need to be made, if any.
Look at post #12 above. It's written by another poster who shows his roast profile for a 155g batch.
how much rest do you typically give your beans?
I like to wait at least 4 or 5 days. I think the peak period is from 7 to 14 days. 15 to 21 is pretty good, too.

jeffgerards

#18: Post by jeffgerards »

Just read through this thread and thought it might be helpful to add my $0.02. I've been roasting about 3lbs a week since June and I roast 8oz (226g) batches at a time so my times might be slightly different. However there are a couple universal tips that I've learned over the last few months...

1) I modified my Behmor to get a temp probe inside the drum and, using that, I have found that the A temp is absolutely worthless. With my batches, by the time I get to 1C, my internal temp is pushing 500ºF. So only use the A temp as a reference point and not an actual temp measurement.

2) One of the variables that plays a considerably more important role than I originally thought is bean cooling. The quicker you can cool your beans, the better the flavor and the less "baked" flavors you will get. Cooling inside the behmor with the cooling setting takes WAY too long. You should be trying to get your beans to room temp in under 4 minutes. I used to take the drum out and shake it in front of a box fan (very messy if you're roasting indoors) which cooled them in about 4 min. However, Sweet Maria's has a cool video that I used to create my current cooling "apparatus". With this method, I can get a 1/2lb batch to room temp in about 2.5 min and it has made a big difference.

http://www.youtube.com/watch?v=tg9VA9gr_PM

3) Using my modded temp probe, I've found that the afterburner has less of an effect on internal temp than the B temp reading shows so don't worry too much about combatting that by switching back to P5 when it kicks in. I've found that when I did that, it would either add more bitterness to the final product or, in worst case scenario, I would accidentally push the roast into 2C when I didn't want to.

4) If you're familiar with Scott Rao's method, I generally follow that as best I can. In his method, the drying and browning stages should be about equal and should be roughly 75-80% of the roast time. Once 1C hits, that point to the end of the roast should be 20-25% of the total roast time. I've found that my time to 1C is pretty consistent regardless of bean type.

Here is my method:

1) Pre-heat for 2 min on manual P5.
2) Stop roast and quickly insert drum loaded with 8oz of beans and chaff tray and restart on 1lb setting and immediately on manual P5 and start external timer. I do the 1lb setting because the afterburner kicks in later into the roast and I've found that to be a good thing.
3) Once B temp hits ~315, switch to P4 to avoid err2. I've noticed that when switching from P5 to P4, the B temp will continue to rise 10-12º before it levels out.
4) At 4 min 45 sec into roast, switch drum speed to high to increase airflow.
5) 1C usually hits around 9.5 min. at this point I take the time to 1C (eg 9 min 15 sec = 9.25) and divide it by .8 with a calculator. That will give you your total roast time with development time being 20% of the roast. You can always roast longer of you want it darker. If I want more acidity in the cup, I will switch to P3 at the start of 1C.
6) at the end of the calculated roast time, I stop the roast, open the door, pull the chaff tray and drum and immediate close the door and start the cooling cycle. Then i'll dump the beans into my cooling apparatus and clean up any mess while waiting for cooling. I roast in my kitchen on the stove so the range hood fan can suck up the smoke that the behmor smoke suppression doesn't get.


Hope this helps! Let me know if you have any questions.

Jeff

maccompatible

#19: Post by maccompatible »

jeffgerards wrote:Just read through this thread and thought it might be helpful to add my $0.02.
I've been experimenting a lot more recently with my Behmor, and have changed up my process in response. Thanks for posting the info about true internal temps, that's quite helpful, and consistent with how my roasts have been responding to blasting P5 heat during the afterburner. My solution is to use the same 1/3 lb batch size, a long preheat up to max heat, and then leaving it on P3 or P4 (depending on what I'm roasting) during the afterburner phase to avoid rushing straight through to second crack like you described.
I did, however, switch to using the 1 lb setting instead of 1/2 lb, which allows more time without the fans and afterburner, making it easier to control the heat prior to 1C, which is still happening around the 7 minute mark for my roasts.
"Wait. People drink coffee just for the caffeine??"
LMWDP #628

jeffgerards

#20: Post by jeffgerards » replying to maccompatible »


Sounds like you've got a pretty good method going. If you haven't seen it, I would definitely recommend checking out out the youtube video I posted. That style of vacuum cooling unit has made the biggest difference in flavor/aroma extraction of any variable change that I've made in tweaking my process. I rarely get baked flavors anymore where I used to get them regularly enough to be discouraging. Also before, when I would see the tasting notes listed on the bag of greens, I could maybe get the more obvious ones like chocolate, caramel, lemon, etc. But with cooling faster, I can often taste even the more subtle flavors like lavender, herbal tea, jasmine, etc. My most recent is an Ethiopian Yirgacheffe that I got from Roastmasters and after about a week of degassing, it tasted and smelled like a chocolate candy bar. It was incredible.