快炒與慢炒---100℃前預熱段

JimH     Posted on 03/27/2011 23:33 I used the same profile as the other 2 beans I tried... 200F at 1:10 300F at 4:45 380F at 7:45 (first crack) 400F at 12:00 To put it in perspective, on my roaster second crack usually starts somewhere around 415F. All of the ramps were pretty smooth and agitation was kept pretty constant. I have roasted the same Brazil since, using a slower approach to 200F(慢一點到達200℉). It was much less ashy at 1:30 to 200F but still somewhat unpleasant. At 2:00 to 200F it regained some of the lighter chocolates and nutty tones that I prefer. If I was to hazard a guess, I would say that the large differential between environmental and bean temps necessary for a fast ramp is more destructive in a less dense bean. I had more or less assumed this was true before trying a fast ramp on a soft bean, but I was already so surprised by the positive results I had received from the Java that it seemed like a worthwhile experiment. One question I do still have is the difference between a fast ramp due to a higher drop temperature and a fast ramp due to greater heat application. Unfortunately, I just ran out of crappy Brazils, so I'll need to order more. It has never ceased to amaze me just how difficult it is to get a good roast out of a low grown soft bean, but that does make them very useful for experimentation. Jim

JimH	Posted on 04/05/2011 11:11

Allen, I tried your profile this weekend. I also tried another few variations, leaving me with a lot of badly roasted coffee. I love the learning process of experimenting with profiles, but hate the waste.

Anyway, I would agree that your profile has better sweetness and body, but it didn't get rid of the slightly burned taste. A hint of ashiness remained. But while I was roasting, I tried variations. I was curious to see if the ashiness was a product of too high a drop in temperature, or too fast of a temperature increase. I did 4 different roasts, keeping almost all parameters the same. What I changed was drop in temperature, which necessitated a change in temperature ramp, and time to 200℉.

The 4 Roasts Case were：
1) 1:10 to 200℉ with high drop in temp (用較高的入豆溫度於 1:10到達200℉)
2) 1:10 to 200℉ with fast temperature ramp(用較高的提溫速率於 1:10到達200℉)
3) 2:00 to 200℉ with high drop in temp(用較高的入豆溫度於 2:00到達200℉)
4) 2:00 to 200℉ with fast temperature ramp(用較高的提溫速率於 2:00到達200℉)

結果：

l   1 and 2 had much better aromas and fuller body, but also had that touch of carbon.

l   3 and 4 had flatter aromas, but no carbon and relatively undeveloped flavors.

l   There also was no significant difference in flavor between high drop in temp and fast temperature ramp in either starting time.

Simply put, it doesn't seem to matter, I would assume because there isn't any thermal mass of the roaster to worry about.

After giving it some thought, I tried the next experiment. I roasted 3 batches, varying the time from 200F to 380F.
再做3個實驗(只變動200℉ 至 380℉的提溫速率 )：

l   2:00 to 200F for all

l   第7:00, 8:00 and 9:00 to 380F(持續時間分別為 : 5、6、7分鐘)

l   full city finish at 第11:00, 12:00 and 13:00 (4:00 from 1st to finish)

結果：

l   The 11 minute roast had good clarity, less sweetness, less body, but no carbon or ashiness.

l   The 12 minute roast was fuller, sweeter, undoubtedly a better roast.

l   The 13 minute roast was even more full, sweeter, very nice flavor development, but it was starting to get a slight woody accent.

All of these roasts had a significant weight loss while roasting, so it is possible that I simply ran out of moisture towards the end of the 13 minute roast. Even so, it is definitely the best of the three. I am now very interested to see how it tastes as espresso.

Jim