I want some coffee!

 I've been struggling with managing the slope of the Bean Temp curve (data from the thermocouple) after 1C. The slope of the line would just tank after 1C got going. Nothing I did seemed to adequately affect that plunge and that threatened to stall the roast. I had looked at a bunch of roast data (most of the 350 roasts I've done plus roasts from other people) and I saw varying degrees of the same problem (at least I see it as a problem). I had tried several things involving power changes and varying fan speed but they just didn't seem to have the controlled effect I was missing. Then I recalled that I had been working with slow drum speeds at the start of the roast, gradually increasing drum speed from D4 to D8 just before 1C. When I thought about what slow vs fast drum speed meant to the beans, I realized that at slower drum speed the beans are staying in contact with the drum for a longer period. Yes, they drop away sooner because of less centrifugal force but the total...

 ... was a foundation built on sand. I'm still struggling with a plan to manage heat at the end of the roast. What I thought I knew, now that I did a chart-by-chart review of over 300 roasts, turns out to be a bunch of roasts with poorly managed heat. I've had this issue from the beginning and apparently just excused the error with "I'll do better next time" with no real plan how. Back to the drawing board.

In the last post I was wool-gathering about heat management at the end of the roast. A little research has helped plug a few holes in my memory.  I reviewed some of the early roasts I did 17 to 20 months ago. I was certain I did things better 'in the good ol' days'. But the evidence was undeniable- I had convinced myself about the good ol' days, but they existed only in myth. As Merle Haggard reminded us, "things were exactly as I choose to recall". What I saw in the charts, however, was the same collapse in RoR starting at about 1C. Exactly what I'm whining about today it's just that I wasn't conscious of the issue. I also looked more closely at the greatest difference between a recently cleaned Drum Temp sensor (IR) and the Bean Temp probe (thermocouple). These days I see about 45F° max difference, but over a year ago that max difference was about 65F°. I had speculated that the difference (65F° vs. 45F°) had to do with using higher Preheat, but ...

Before Blogger shit-canned my work for the 3rd time, what I wanted to post about is my issue surrounding the runaway loss of heat at the end of the roast. I didn't have to deal with it when I started with the Bullet back in Jan 2019, but it's a familiar quirk these days. I whined to an internet acquaintance about it and Stuart's feedback was phrased in just the right way to make me see what I've changed that needs to be unchanged. He said: As you note, one of the perils of the Bullet with it lacking any significant thermal mass is once you drop off the cliff with thermal momentum, you’re kind of screwed. I had whined that I was already at P9 (the highest power setting on the Bullet) and 'there's nothing left in the tank to get heat into the drum'. This has been happening at the end of the roast as 1C starts. Rate of Rise (RoR; the 1st derivative of Bean Temp) measures how fast temperature in rising in Fahrenheit degrees per minute (F°/min). As long as the ...

... but you can fool me pretty easy. My Aillio Bullet R1 roaster has a device built into the front plate that allows the operator to take a look at the beans during the roast. It's a little tubular scoop that can catch a few beans as they crash around inside the drum. Gives the operator a chance to see the bean color and get a whiff of how the roast is progressing, It's called a 'tryer' and it's pretty slick. Recently I've been playing with drum speed. Drum speed wasn't adjustable when I first got the Bullet (it should have been). When I upgraded the power board to V2 (and the control board as well; my Bullet is now a V2 Bullet) I suddenly had control of drum speed. At the suggestion of one Bullet owner, Glen Junkert, I started using a lower drum speed at the start of the roast (D4) as part of something Glen calls a 'heat soak' prior to increasing the power to get to roast temperatures. Midway thru the roast I start increasing drum speed as the roast...

We finally got a cool day- high of 82°F. If this were March it would have been hot, but this is July and you take what you can get! And what we got was 4 batches of COSTA RICA don Oscar Limones' finest. I did a pound of this in mid-June and really liked it. Then 9 days ago I roasted some and got some really odd behavior after 1C: the temperature dropped off so fast as 1C began I thought the power board might have failed: Ideally (if I manage to do my job right!) I should see a gradual decline in Rate of Rise down to about 10F°/minute by the end of the roast (the green line I added to tthe chart). Instead RoR dropped like a stone and I wasn't sure all the button pushing was doing any good. Eventually it recovered but I was very uneasy about the roast quality so it sat in the fridge. So this time I was on the lookout for odd roaster behavior for the whole roast since I couldn't believe this was related to something specific to the beans. Notice the difference? Neither do I! O...

Sweet Maria's had a new offering that sounded like it might work for me. They call it Costa Rica don Oscar Limones which is a farm in the Tarrazu valley... about 6,000 ft elevation. From the Cupping Notes- The name " Limones " may seem a bit disconnected from what's in the cup. Limones isn't a bright, citric coffee. Rather, it's more of a simple cup profile, with sweet to bittering flavor characteristics that respond readily to roast development. City+ roasting highlights flavors of toasted sugar and moderate acidity like white grape juice, with softer chocolate finishing flavors drawn out in the aftertaste. If you're for more of a chocolate-toned cup, extend roast development into Full City, or even Full City+. In that tight roast range you'll be rewarded with bittering cocoa flavors, developed roast tones, reverberating bass notes and carbonized sugar bitter-sweetness in the aftertaste. Limones also delivers as espresso, a "classic...

I had thought I'd do 3 or more roasts but got side-tracked reading some info I'd gotten on Aillio's Roast.World forum related to heat-soak. So I managed a single roast of some decaf (still struggling to roast decaf I'm excited about!). The roast I did sounded interesting: ETHIOPIA Organic Limu Kossa SWP (decaf). Not exactly a 'chocolate sundae', but still... The Cupping Notes told me I'd have to go a little dark (as usual). I tried to merge that target with another attempt at incorporating a 'heat-soak' described by Glenn Junkert (@quartzglen on Roast.World; formerly the roaster at Hunter Bay Coffee in Missoula, MT). The heat-soak requires changes in drum speed (as well as power and fan settings) . Since I can control drum speed now, why not give it a whirl? "Fragrance and aroma are potent. Complex molasses and sorghum sweeteners, pine syrup aroma, dried berry, raisin and prune, big cocoa roast flavors when roasted dark. City to Full City. Goo...

It works! When I was an engineer working at Lockheed, I learned that there are good reasons management didn't want engineers touching tools. The techs were good at their job and I wasn't. So when it comes time to modify electronics I prefer to leave that to the competent hands of those who are good at it. That was over 25 years ago. Now when something needs fixing it's usually up to me to get it done. But I sweat bullets till I know I didn't screw up the work. In this case it went well. Boot-up is a little different as already mentioned, and I now have control of drum speed. Most importantly I had no alarm sound while I was roasting which is a huge relief. Operation is outwardly the same as before but there are subtleties in control behavior that suggest I may have more responsive control of the roast. So I gave it a try. This is the first of only 2 roasts before the temps in the shop were over 90°F ( yuk! ). I tried several different things that demonstrated I need to ...

Today it's Honduras Comayagua Nueva Alianza ( Comayagua is the place; Nueva Alianza is the co-op or farm that supplied the beans). I roasted this batch to about City+ (C+) which is a little darker roast than the minimum (and I think I could have gone a little darker). As a generalization, beans are considered 'roasted' anytime after first crack (1C). A roast which is stopped just after 1C is called City roast (C). And City roast denotes the start of the color pallet which runs from City (the lightest shade) and gets progressively darker as it moves thru C+, Full City (FC), FC+, Vienna (V) to French Roast (FR). So each roast level (C -> C+ -> FC -> FC+ -> V -> FR) is darker than the preceding level. At some point around FC+ the roasted beans start showing signs of oil on their surface. After FR the beans are pretty much history in terms of drink-ability and are likely to burst into flame inside the roaster if the roast continues. There are 2 ways to watch t...

That's our traditional question every morning as we finish eating and uncover our coffee for the first sip. It's a morning ritual that doesn't vary much and I look forward to it. It gives me a chance to talk about what I roasted. I skip the flowery descriptions that are in the cupping notes below- they're mostly lost on us. This morning's Colombia Timaná was pretty good so it rates a +1 on may makeshift  -1|0|+1 scale... no fractions allowed. Celia was delighted but I thought it was missing something. Yet the preceding day I was very happy with these same beans. So it appears it's sensitive to the brewing process which recently has been changing. (Guess I'd better do one about that too.) This morning we had Colombia Timaná Vereda San Marcos from Sweet Maria's- Cupping Notes: The dry fragrance has smells of sweet baked goods, oatmeal raisin cookies, banana bread, and more. The wet aroma is along the same lines and shows sweet dried fruited smells at C...

I like to put labels on the degree of roast but, lacking structured experience (training by someone with cred), I have to plagiarize from sources I respect. The label I assign to a roast to keep track of what I've done and the code (C, FC+, etc. below) fit with the cupping notes that Sweet Maria's provides for their offered green beans. I pirated these images from the Sweet Maria's article " Using Sight to Determine Degree of Roast " . His article is better than my summary here but this is a reminder for me of what I'm looking for ina roast.. Roast Name     Symbol  Description  Image  Temp  City  C  Lightest brown roast for the  variety involved (varies);  texture is smooth but not  polished. 1C is ended (hard to  determine as there's not a distinct  end)..    ~ 426°F  City +  C+  Roast is a little darker than City  and the beans are starting to look  a little polished; no oily drops ...