GregR wrote:Firstly- on the last few roasts the drum is scracping on something for almost exactly one minute, starting only when I drop the beans in. Even after I removed the drum for cleaning this happens- that was something I was going to fix this weekend too... busy weekend coming

My ancient HT does the same thing. On mine, I am pretty sure it is the heating element. Once it warms up a little, it "expands" back toward the roaster wall and the scraping noise stops.

Jim

Thanks John for the feedback.
You've got a completely different approach- and I'm all over it Are you roasting for espresso with that sort of profile? I should say, I'm all over it once I figure out how to get 9 minutes to first crack.
When you say "tanning stage" do you mean end of drying stage?
A rough estimate is 125-150 roasts so far. The beans start to get tan (which I think of as end of drying phase), generally at about 5:30-- I drop to P70 when the display is at 285-290F (usually right around 3-3:15) the P50 at 300-305F and use the fan to keep the temp rise slow (8-12F/min +/-) til 330F then full power no fan. Maybe I'm dragging out that drying phase too long. I have to say the roasted beans generally look beautifully even using that technique, tipping aside
Interesting about the Variac- I thought it wasn't need for a Hottop? I have one sitting in the closet left over from my Behmor days.

GregR wrote: Rama- my understanding, probably based on what Jim wrote though I can't recall the exact article, is that the ramp up to first, if slow, reduces brightness but stretching things out at the end of the roast increases sweetness. A fast ramp to first crack will keep bright coffee bright. So I'm worried I can't get a fast ramp while still reducing the heat during the drying phase. If that 11:45 is slow then that also points towards the heating elements... I think.

A simple analogy for correlation between brightness(acidity):sweetness and ramp:finish is your stereo. Think of the ramp like your treble and the finish/stretch as your volume.

Keep the ramp short and compact to crank up the treble and have the acidity sharp and clear. Keep the finish short and compact to make it's impact louder on your tongue. The longer you stretch out the finish, the lower the volume is on the acidity and easier it is on your tongue. The roast degree will also impact the overall flavor/acidity profile. A short stretch for a dark roasted coffee will obviously have a different acidity profile than a short stretch, light roast.

The point is, you have a few variables to play with here. Your taste preferences and coffee types will obviously drive how you govern these variables. There is no substitute for experimentation. You simply need to roast a good coffee several different ways and sample it to understand the product.

As far as tipping goes - this is simply a matter of controlling your MET heading into the stretch. It's fine to drop the hammer coming out of drying, but when 1C is within earshot(vangaurd beans popping), it is too late to throttle back. If you play with power reduction times/temps, you will notice there is a sweet spot. You can find this by recording 1C temps. If you are getting "low" 1C temps, you are coming into 1C too hot. Keep playing with settings (time offset, power, fan etc) until you can bring your 1C temps up a few degrees. Not sure if you have a good BT probe installed, but you really need one to get serious about your roasting.

One other thought on the HT. The fan is nearly worthless for heat distribution and convection purposes. It can be thought of like the brakes on your car. It is helpful to reduce roast velocity, and that is about it. I found my learning curve on the HT went out rapidly when I kept the fan setting static throughout a roast. I would try keeping it at a setting of 1 or 2 throughout the roast.

Cheers,
~j

PS - A variac works wonders on normalizing the power on a HT. It would be a worthwhile investment. If you combine it with a Kill-A-Watt, you can standardize line voltage which will save you a lot frustration.

Wow- thanks for all the great info.
Got a Variac, got a Kill-A-Watt but haven't been using the Variac because I read that the Hottop does not benefit from it. Also- power is very stable here, going from about 119-.5 to 121.5- at least I thought that was pretty stable?
The analogy is very easy to grasp. Roasting for espresso one wants to tame the volume of the treble right? Stretching out the finish is the big difference in roasting for espresso (my goal 90% of the time) v. coffee no? I'm asking because I'd hate to think I've been misunderstanding this important principal and appreciate the input from experienced roasters very much.

As far as tipping goes - this is simply a matter of controlling your MET heading into the stretch. It's fine to drop the hammer coming out of drying, but when 1C is within earshot(vangaurd beans popping), it is too late to throttle back.

Aha! I'm having an aha moment The tipping is occurring just before first crack when the power is still at 100. A fine line to walk there. I've been targeting the power drop to only 30 seconds before first, and- this is telling- on my last tipped roast first came sooner than expected with only 20 seconds or so from power drop to those first vanguard cracks.
I'll be installing that probe this weekend. Regarding the fan recommendation- with the replacement filter I got the fan has far more impact than with the stock filter. If I put the fan on 50% for the whole roast I don't think the temp would ever top 300F- it really made that much difference. I like the greater control it gives me but, and I don't quite grasp why it would be, but I'd put a stock filter back in there if it'd improve my roast quality. Of course I'd have to relearn how the roaster reacts to the fan all over again

The Variac/Kill-A-Watt combo allows you to adjust your line voltage throughout the roast. You can read the Voltage on the KAW screen and notice it changing as you adjust power on the HT. Give it a shot. You will soon be able to reproduce roasts much easier with this insight.

Re: MET/tipping

The reason it is such a tight rope going into 1C is because the beans are very dry and vulnerable. Water is a great conductor of heat and allows the bean to abosrb thermal energy more efficiently. Going into 1C the beans are dry and unable to absorb heat as well. This is also the time of the roast when heat application is somewhat high as you want a quick ramp generally speaking (it preserves terroir). This needs to be attenuated properly in order to maintain enough momentum to reach target roast level in the desired time frame (stretch/finish).

Re: Acidity/Espresso

Totally depends on your taste buds. Lately I have been really digging a moderate ramp (9:15 1C) with a longer stretch for espresso (4:45ish) for light roasted beans (city+). I find this combo really highlights the terrior of the bean and tames the acidity enough to make killer straight shots. It can be tricky to balance this style of roast but the results can be delightful. This profile seems to work better on higher acidity beans of course. If you were roasting a low acidity bean, you may want to shorten the stretch a bit(or risk having a totally flat profile in the cup) and possibly bump up the roast degree (focus on bass notes, caramels etc). Like I said, experiment! It is the most liberating and fun part of home roasting. Buy 5 and 10 lbs bags so you don't to be bashful about trying different roasts.

Re: fan

From a stock hottop, to yours, to JohnB's ultra modded HT - I guess there is a lot variance in application. I just know I had a lot of luck on mine keeping the fan setting at 0 or even 1 throughout. I used it to help buffer my power settings and timing when they were off a little.

BT Probe:

I really dig having mine through the back wall. It is trickier than going through the bean chute, but well worth it in the long run. Take care to see that the probe sits in the heart of the bean mass. This will help yield really accurate and consistent numbers. My HT consistently hits 1C at 395 (+/- 4*). I prefer a 1/16" TC vs. a 1/8" as it is very responsive. A 1/16" TC is also flexible enough to bend into place, making it easy to pinpoint center bean mass.

This has become a really informative thread for me - thank you!

I agree- the info in this thread is priceless.
Jammin- thanks for all that! In my search for an answer on how to improve things it looks like I also found out that my Hottop is taking too long to get to first crack, even with full power. So I'll use the Variac on the next roast and see how that works. Randy's comment plus the other info in this thread have me thinking it's time for a new heating element.
Thanks for the thermocouple input. I am heading in that direction.

With only 150 roasts there is no reason to suspect the heating element due to age, I'm approaching 400 roasts on my HT with approx 350 of them with the stock 720w element & it is still working fine.

Regarding drum contact it should be easy to see where the problem is once you remove the drum. If it is scraping you'll see the marks from metal to metal contact. Mine started hitting the rear mounting plate at one point but opening up the gap between the body & mount cured that.

GregR wrote:Aha! I'm having an aha moment .. The tipping is occurring just before first crack when the power is still at 100. ...

Try an experimental roast to learn about the exothermic properties as well as the "ambient" heat in the roaster towards the end of the roast (last 4-6 minutes). By now you should have a very good idea as to the display temperature at which 1st begins. At least five degrees (or maybe even 7 or before that start dropping the power. See how low you can get the power and still maintain a slow rise in temperature and reasonable continuance of the roast. I have had roasts hitting the beginning of second when the heating element had been down as low as 30%. It is interesting to see how easily the temperature rises at the end when the heating element had been at 50% by the end of first, and at 30-40% for the last 1.5-2 minutes. This is a critical time as has been mentioned above in others' posts and I think that things generally happen so quickly that it instills a sort of panic and intent concentration (particularly with new home roasters) when it is a good time to relax, slowing down your own heartbeat as well as slowing down the roast.

I am sill learning a lot about roasting. As I was saying to a pro roaster at the show last weekend, when you think you know everything about roasting, it's time to quit roasting because you know nothing.

Roasting properly is not a matter of life and death.. it's far more important than that.

Let me share a story here. A pro roaster acquaintance of mine was at a demo of a small home roaster (about 3 or 4 years ago) that was customized with an interface that showed an excellent real-time graph of the roast. he glanced at the screen and told the fellow roasting that he was "teasing the roast," explaining that he was bringing the roast along too slowly, and that it would taste like balsa wood. When the roast was done a pot was brewed and we got to sample the coffee. Without exaggeration, the coffee tasted as if it was brewed using coffee beans and one of these:

Italyhound wrote:This has become a really informative thread for me - thank you!

+1 !