Environmental temp (the one outside the roaster)


I live in Florida where there can be relatively large temperature fluctuations from week to week… Something I’ve noticed is that when I roasted a Sumatran peaberry I’ve been working with was that when the room temp was in the 60F range the beans retained a lot more acidity and clarity but when I roasted in avg. of 80F ambient room temp the roast went heavily on the Millard-y side. Anybody experience this? The roasts were within 3 weeks so I doubt it was the bean storage.

How to Taste Coffee

Hi @deven.patel411! Interesting note and we have a couple thoughts. Because the roaster is measuring input temperature, if the beans are cooler to begin they will be slightly less developed. Starting with warmer beans would increase the stage the beans are at earlier in the roast. I know there are many professional roasting operations that have climate controlled rooms for their green coffee. It keeps the roasts more consistent and their greens tasting good longer. The other thought is that maybe the small amount of difference in the casing and metal has an effect. Unlikely, and easily avoided by doing a really quick warm up roast with no coffee in the chamber. Has anyone else found similar?


Well, I think I had a simillar effect, noticing less development on a roast I did a month ago than when I roasted the same beans in summer (ikawa profiles, i think colombia and kochere or guji). A difference not big, but very well noticable. I always do a warmup with no beans, so probably a bean temperature is the possible reason. I would think there could be a 10degrees C difference in environment temperature.


I actually made a slight error, in that I roasted the wrong profile. Not a completely diffent profile just one with a slightly moded fan setting. However after just roasting the right profile I still stand by my original statement. I have not opened the roaster yet (and won’t be until the warranty has ended). But since this aluminum shell has such a high thermal conductivity I would theorize that it’s not the input temp which can be quickly adjusted but rather the negative change of free energy dissipated through the metal shell.


How about keeping green beans in the refrigerator to stabilize the temperature and humidity (defrosting fridge usually has a stable if dry humidity standard)? Of course your beans are starting off cooler, but at least one could standardize the roast outcome.


@cooley I know some commercial roasters will keep beans in a cooler environment, although maybe not that cool. It could work though! Like you said, the profiles would need to be adjusted to take that into account, and may be less “shareable”, but it could be interesting to explore


I have also seen its not that hard to make some small climatized box (originally say for a computer or bunch of them) … set it to 20C and keep the beans inside … The question here is, if its really worth the troubble. One roasts very small amount of coffee, and its easy to adjust the roast … so maybe using it as a bit of motivation to learn to do those small adjustments, that could help a lot with being able to finetune roasts for beans without profiles … :smiley:


I don’t think you have to go that far,. I just had to main questions in mind 1) how much of a temp differential will make a difference? 2) some people are on other sides of the world experience different climates so keep that in mind.


Thanks guys - great questions for us to keep in mind with testing and communications


I would think it depends quite a lot on the resolution of ones palate, and his measure for a difference Deven. I think if I have given say my set of 3 or 4 roasts spaced out 30s to someone, he might no be able to see any difference, and if I had given the same ones to a professional with high sensoric resolution and knowledge, it would have very big differences for him.

My view of this enviromental temperature is, that its for sure good to hint the people using ikawa this may have (well it sure does have) some influence, but for me … I just keep that notion that it is a parameter in the roast, like say environmental humidity is … it sure has an effect, but for me within the bounds of - hey this roast is tad bit different today, thats somewhat nice :smiley: its not yet had an effect that I would think, it used to be such a nice roast and today I dont like it … But … as I said before I like variety, so the slight shifts are in my favour of exploring from slightly different angle.


As for my suggestion that one keep the green beans in the refrigerator… don’t. I did more research after I posted that idea (not the suggested sequence or events) and conclude that a standard refrigerator is too cold, and more to the point, too dry. It would, however, provide some consistency to the roast. A wine refrigerator would probably be better! As to Pavel’s comments about palate resolution, I find that my reaction to any one roast changes a bit every day. I use an expresso machine, weigh the grounds in the portafilter, then as coffee (20g of grounds produces about 40g of espresso), and I time my pulls. Yet the flavor changes as the beans rest. I tend to like the results most about 4 days after roasted. There are so many parameters at play!


Thanks for looking into that @cooley! Humidity is a big part of coffee storage, great point


I did not want to step into that one, but now I will add, that a repeatable reaction from any barista or roaster I heard reacting to someone that mentioned fridge or freezer for storage - be it green or roasted - has been a strict no-no … like its really not a good idea. So … its nice your own deeper look into it also seems to confirm this. I also remember some thread from home-barista, where there was a lot about testing different ways how to prolong life of both green and roasted coffee, some using cold environments or nitrogen … cant recall exactly the reasons, but I remember two things … it did not seem to lead to a conclusion that it helps (so I stopped thinking about that) and - /and this one I remember because it seemed really to show something about the material/ - when using Nitrogen with the roasted beans, someone found out it works if done correctly (it helped to keep the material in a better condition while closed in nitrogen) but it also degraded more quickly after opening or something like that … its been quite some time so - if anyone has it in better memory please correct me if I made a mistake there.
What I took from this one was - I dont bother with any cooling or other fancy stuff at all. I vacuum seal my valuable greens to keep them out of environment moisture, i keep them in a dark place but room temperature, and when have any roasted coffee I try to go through it as fast as I can :slight_smile: usually I try to stay under 2 weeks from roast. Of cause … stored in a sealed jar with valve, in dark place but at room temperature. :slight_smile:


An interesting and well written article relevant to this thread…


wow … what a reading! Will have something for tonight as a food for thought :slight_smile: Above mentioned testing was only regular freezing, or using nitrogen gas to not let oxygen do what it does best and oxydize away …
Now I recall someone mentioned freezeing his beans because of exatly this back at KS chat. Looked crazy to me - and hahaaa … here it cometh! :))


Makes sense, though it really hurts my brain (all those respectable professionals still pop out in my head saying nono, please dont put the coffee in there) … but when vacuum sealed (and not taken out from freezer in a jar, opened for a dose with a condensation of water happening all over the coffee) all the rest sounds reasonable. That sort of thinking (that if freezing works for my fruit and vegetables, it could work for my coffee too) led me into looking for some information those few years ago … And I think that most of the negative sides that made it unclear whether ist good, were connected to the way that those home users do those mistakes along the way and have water in the air in contact with coffee, condensating on it or things like that …
Seems like … when its packed in chunks to be used in one go … this should be ok.


Roasting coffee and cooking are in the same family. A lot of correlations can be extrapolated.


Looking at that other part (deep freezing to supposedly create better distribution of fines when grinding) - and, I have to say I would be glad if someone used to reading charts like this can confirm (or prove wrong) my feeling from it.
I just do not see effect on the chart that would make me think of a big impact, I see for sure slight change in shape of the hill of fines, being a bit tighter, but overall there is still nearly the same amount of fines to my eye (so they have to overextract anyway, right?).
So - is this curve reshaping worth having bunch of dry ice or whatever … and worth that step?

Well it was certainly worth it for the jury, but … would the barista and coffee possibly win even without that step?

I put it on my list of things to test,and I will test it against my “narrow band” extraction :slight_smile: :slight_smile: a good excuse to have some fun with dry ice …


I think the deep and sudden freeze does two things 1) break open more cell walls 2) make it so the beans are “cut” rather than ripped.

I’m not sure just my guess.


My inuitive view of that grinding effect is, that they are more brittle deep frozen (fines are there in not much less quantity) but brittle in a more consisten, predictable way, so that the size of particles is more simillar - size of particles forming that lobe of fines. But, to me it looks like a kosmetic change - because the presence of fines means for me also presence of overextraction, its only more focused overextraction, less blury … but still.

When I did my tests with separating the “narrow band” … say 400 - 600 microns, and making espresso like that, it completely changes the game. The espresso gets very clean, straight … well separated tastes … also way less body and bass notes (no fines). Its a whole different world. But I did not have enough time to see how far the extraction can be pushed with that … still very much to explore there. But it changed the extraction in a radical way, and quite obvious why … thats why I wrote about it. When I have some idea of that size of change, its hard for me to see that rearranging fines as a big improvement …but maybe I dont see something important.