Frozen coffee beans: Grind from freezer or room temperature

#1: Post by **LBIespresso** » September 6th, 2018, 2:26 pm

When I grind from frozen I need to grind coarser than when I let the beans get to room temp. I have not had any issue with condensation when I bring the beans to room temp.

Now I would assume I need to grind coarser due to more fines or a particle distribution that skews towards the smaller. That said I would like to try to avoid particle physics and fluid dynamics in this thread and just focus on taste as much as possible. Obviously it will be impossible for some to make their point without but within reason let's do our best to limit this to taste.

For a few days now I have had 2 shots every morning one from frozen and one frozen then warmed to room temp. For me the frozen shot was both sweeter and more complex. This may just mean I need to do a better job of dialing in the room temp shot but I am curious.

For those that have done both: What is your experience?

#2: Post by HB » September 6th, 2018, 4:57 pm

There's been several recent discussions that may be worth a look: grind frozen coffee beans.

September 6th, 2018, 5:33 pm

Thanks!
I had looked through those in the past and just did another quick perusal. I didn't find anything about thawed vs straight from the freezer comparison for taste. Don't get me wrong, I love coffee science, but I was curious enough about this to try it myself before posting and was hoping others might chime in on their experience.

#4: Post by HB » September 6th, 2018, 6:28 pm

It isn't always easy to find, I guess. Anyway, the merits of freezing coffee has been argued with no consensus. Some excerpts for reference:

BaristaBob wrote:I have been freezing my beans per dose for about a year now. I was one of those that started a thread here on freezing beans and subsequent quality in the cup. As others including Mike have noticed a change in grind setting upon freezing (going finer), and improved flavor in the cup...the temperature out of the grinder is a moot-point, at least in my experimentation using my Rancilio Rocky grinder. By IR temperature gun, my beans go into the grinder at around 4F and after 15 seconds of grinding 18g of beans hit the pf at 76F...basically room temp. IMO, the flavor improvement is all about grind particle size distribution (which is my scientific research background) and being able to grind finer produces increased EY. YUM!

From Frozen coffee beans - espresso brew temperature?

aecletec wrote:Other research has shown that cooling the bean changes its grinding particle distribution. I don't know where the cutoff for this would be in terms of heating. Do you have a source for the volatiles hypothesis?
One thing I do know, however, is that quality focused cafe owners I've talked to disconnect the heating element on their Mythos because it increased their inconsistency (after testing).

That's from Monolith Conical Grinder and Freezing Coffee.

Peppersass wrote:I think this is half right and half wrong.

Half right: It's been observed by many that frozen beans produce a finer grind at the same grind setting as the same unfrozen beans. It makes sense -- the beans are more brittle and produce smaller particles when fractured.

Half wrong: I don't think the longer extraction (i.e, lower flow rate) is caused by finer coffee particles having more surface area and thus absorbing more water. I believe it's the same phenomenon that always happens when you grind finer: the smaller particles pack closer together, impeding the flow of water.

Further, a finer grind will normally extract more, both because of greater surface area and more contact time due to the slower flow rate. The question is whether simply grinding a little finer will produce the same extraction as freezing the beans, or whether the particles produced by the frozen beans introduce some other quality. I guess it's conceivable that frozen beans produce a more uniform grind in low-end grinders, and hence a more even extraction, but that's just speculation.

And that's from Freezing Coffee Beans For Flavor Improvement. The mother of all writeups was Ken Fox's and Jim Schulman's Coffee: To Freeze or Not to Freeze, though it did not consider the merits of direct-from-freezer grinding.

For what it's worth, I've never done a side-by-side blind taste test of frozen versus room temperature coffee beans, so I have no opinion.

September 6th, 2018, 8:10 pm

Thanks Dan!

I appreciate the time you spent putting those together. It is helpful to see it all together.

I definitely taste a difference from room temp vs frozen vs frozen then brought to room temp but I guess I need to play around a little more. If I find out anything interesting I will report back.

September 7th, 2018, 1:48 pm

Indeed there definitely can be taste in the cup differences between the above variants you mentioned. Most of my "research" was focused on making my Rancilio Rocky punch above its potential, and indeed freezing my beans overnight and immediately grinding them improved flavor in the cup for almost every bean I've tried (and it's been many)...from medium-light to dark. I'd say it's diminishing returns the darker the roast. Just purchased a light roast from Klatch "Out of Africa" blend, so I'll be testing that once my MonoCon arrives sometime in October. Then my experiment will pit Rocky vs. MonoCon (absolutely not fair I know...however flat vs. conical), grinding temp of beans (frozen vs. room temp), and roast level (light vs. med-dark).

Should produce some interesting results. I'll report back next month.

September 7th, 2018, 2:19 pm

Looking forward to that! I also will have a flat (Monolith) to compare to a conical (HG-1) come October. Hopefully we can compare notes and come to some helpful findings!

September 7th, 2018, 4:45 pm

I've done it both ways, and I honestly can't tell any difference. For those who think they can, I'd encourage them to have someone help them to do some "blind" testing. Sometimes we just get the exact results we're expecting.

(We need to remove "confirmation bias".)

And if we're able to consistently tell the difference, can we be certain it was the temperature that causes the difference? (Can we identify and isolate "confounders"?)

Jack

September 7th, 2018, 6:50 pm

JR_Germantown wrote:I've done it both ways, and I honestly can't tell any difference. For those who think they can, I'd encourage them to have someone help them to do some "blind" testing. Sometimes we just get the exact results we're expecting. (We need to remove "confirmation bias".)

And if we're able to consistently tell the difference, can we certain it was the temperature that causes the difference? (Can we identify and isolate "confounders"?)

Jack

1 year into making espresso with a manual grinder and a manual lever machine it is very unlikely that I am consistent enough with all of the other variables to isolate just one. This is why I asked to see what others have found.

#10: Post by **erik82** » September 8th, 2018, 1:04 pm

For me grinding frozen worked best tastewise. I always freeze in 46.5gr portions (3 espresso) and take a container out in the morning and transfer them to airtight containers when I get home from work so age of the beans was the same. I had been drinking one bean a whole week and just for fun tried to grind frozen. I had to adjust the grinder a bit coarser and it tasted better than all of the shots before that. I didn't have any expectations so no bias here.

I did this experiment a couple more times and always found grinding frozen better. I don't have enough containers (vitavac) to freeze 1kg of beans so for now I just freeze portions of 3 espressos at a time and defrost them.