Environmental temp (the one outside the roaster)


The science behind the effect of freezing on grinding roasted coffee


Thank you Geoff


Thank you Geoff … will go through it during the day …
Bad for me, that those logaritmic scales are so non intuitive to understand for me :frowning: but from the pictures … it still looks like … there is more fines/more smaller fines …even though in tighter curve. Intersting what will show up for me from the text there.


There is a lot I find wrong with this article, a lot of assumptions…no I will not get into it here because to most it will seem like I’m just trying to blast him and his hard work which I find admirable. If he wants to message me sure I’ll talk about it but it was a good attempt none the less. @Geoff_IKAWA Thanks for the read it was interesting.


@deven.patel411 may I ask you just to tell me\us how you read those graphs? I am no used so much nor to the log scale neither using particle counts and not weight, so the shape that I am used to see it quite different from the one presented, but as I wrote, I can not imagine any large effect of if when I try to understand whats presented on them. You do not need to go into anything else, only how your read that graph with your eyes.
Thank you.


which figure were you interested in 3 or 4?


Fig 4 … thank you Deven.


Ok I wouldn’t worry about not being able to decipher the figures. Basically it says that the colder the bean the sweeter. Temperature doesn’t really affect the particulate average that much. The most number of smaller particles were found in nitrogen then dry ice then freezer and last room temp. The average size of particles go in the same order except room temp is better than freezer.

As for the sweetness I don’t know how he is measuring it my guess would either be Brix or maybe he’s taking the gravity. Again it does not say. I’d take his findings with a large grain of salt.


Thank you Deven. My confusion turns around two points. 1 - as I wrote to my eye the changes seem to be minor, and even worse 2 doesnt simillar surface area in smaller fines mean even more overextraction?


Yes it would seem quit minor or maybe not. The way he measured particle size was to assume a spherical shape of the particles but the shape in reality is very irregular.but all of it doesn’t really matter because the barista takes these things in consideration of all the variables and can adjust other things, tamp, temp, pressure etc to compensate. One could also assume that these grinder companies have already done similar research leading to impractical answers or answers well ahead of a consumers willingness to accept either price point or something els to not make it commercially available, for instance gas flushing has been common practice in Illy for a Very long time, on a commercial production it is possible but in a household, not so practical yet. Though nitrogen and co2 are creeping their way in via soda steams, whip cream, liquid nitrogen, liqiuid co2 for the prosumer /hobbiest.


So I roasted the exact profile today, in the exact order, with the exact same weight, but not quite the exact same beans(as they have already been roasted, but from the same bag). It was 73F yesterday and its 56F, both temps taken at the time of roast. And for sure, there is an effect from the environment, could MORE POSSIBLY be the humidity as it was in the 90’s yesterday and 70’s today. Which also has an effect, maybe more of an effect than the temperature, since it makes sense of where the probe is and how it works. Anybody with crazy humidity fluctuations see any differences?


Well if the humidity has a lot of effect (and it makes sense for it to have) I am lucky to keep a stable (relative) humidity at home, at around 50%



The humidity I have found to make such a difference that I now have started recording the room temperature and relative humidity in my notes.

For the past week I was not able to get blueberries in my Ethiopian DP which I was able to on my first roasts of the bean. Today RH was 75%, not the 81% when I captured the flavor first but the aroma before and during 1C was much blueberry and the bean tasted like the aroma. During the week the humidity was around 50%. What’s also interesting to note is that I would associate fruit tones with roasting shorter or lighter but if higher humidity is supposed help roast the coffee more, then it would also seem more development before 1st helps with fruit in this coffee, using: Marshal Etheo (v.4) profile. I’ve listed in the Ethiopian bean thread. Just thought I’d share with you guys.