Aside from it being a long day, with several hours driving in the rain and fog in each direction, I had a very interesting hour and a half at the Diedrich factory in Ponderay (next to Sandpoint) Idaho. The long and the short of the visit is that my head is now so full of conflicting information that I'm going to ask you, gentle readers, to completely disregard everything I have ever posted on the subject of coffee roasting. This is especially true when it comes to roast time and temperature parameters. I'll explain a bit more what I mean below.
Here's a picture of Stephen Diedrich next to my new roaster.
The plan had been to meet up with the head of tech support and production today, who would show me the operation of the roaster before it would be loaded in my car. She was unable to come into work today due to car difficulties and by coincidence Stephen Diedrich, the owner of the factory, was around and he spent time with me to demonstrate and check out the roaster. In the process we talked about how to roast with this roaster and about his philosophy of roasting. A lot of the information I received today basically contradicts a lot of what I've learned over the last 6 or 7 years, plus contradicts much or most of what I have read in this and other similar online roasting threads. I'll give a couple examples of what I mean below which will perhaps clarify while I feel utterly confused at this point.
Stephen does not like the term "drying phase" and does not think one should seek to get the moisture out of the beans early on in the roasting process. Residual moisture is useful in the latter parts of the roast process and in fact with some beans one should seek to retain moisture even at the end of the roast.
Another point he made which was similarly discordant with my previous impressions was that first crack should not occur until 11 to 13 minutes into the roast, and that this would not be the same for each type of bean rather would vary but should be consistent for XXX bean (e.g. you don't shoot for the onset of 1st crack to be between 11 and 13 minutes, rather, each bean has its "right" time and once found you should attempt to get to this point each time you roast that bean, and it will be between 11 and 13 minutes into the roast). Likewise, he did not like the idea of an interval of 4 to 5 minutes between the onset of first crack and the end of the roast, rather he felt that 2 to 2.5 minutes was better, even for espresso, except if one was using a high acid coffee where the goal was to tone down excess acidity. Otherwise, he felt, that an interval like 4 minutes would flatten out the coffee too much.
There were other points he made but I really do not want to go into them in any great detail. Rather, the overall "take-home" message was of an approach and philosophy to roasting completely different than anything I have done before and different than most of what I have read on online forums. He is very much against even the IDEA of freezing roasted coffee. He certainly believes rather strongly about his approach, which he believes produces the best results.
Roasting equipment differs considerably among the various manufacturers. Exactly how much this impacts the coffee and how it relates to different equipment and how it should be used with different sorts of beans is way beyond my level of expertise. I am not willing to conclude at this point that what I have been doing over the last years was valueless, since it seems to have produced some pretty good results in my hands. Some of this I have even tested in a relatively formal and singled blinded way, such as the interval between onset first crack and the end of the roast. Jim Schulman and I did this test several years ago, with coffee having an interval of about 2.5 minutes vs. 4 minutes after onset first crack, and we both preferred the 4 minute interval 100% of the time in blind tasting. I have written this up before in prior threads, and it was the only such blind tasting test I have ever done where both of the tasters preferred one coffee 100% of the time and could quickly tell which sample was which in two blindly presented samples pulled at the same time from essentially identical espresso machines.
So how am I going to process this whole experience today? My conclusion at this point is that Diedrich builds very fine equipment which is capable of a degree of control over the process that I have never had with my prior equipment. This allows one to control time and temperature better than I ever did before. I am not willing to conclude at this point, however, that there is only one best way to roast any particular type of coffee. I think there are probably at least 2 and likely even more ways to successfully roast a given coffee.
My days of being dogmatic about this stuff are over. If you tell me that you get good results with your roaster doing something completely different than I am used to doing with my roaster, my attitude going forward is that I have no proof that you are wrong until I taste what you have produced and can conclude that is not good on the basis of having tasted it, personally.
That's where I am on this stuff today, but I might feel differently in a few days after I have the chance to try out this roaster and to think on these matters a bit more.
ken
...split from US Roaster Co. 1-lb Sample Roaster by moderator...
