WHAT I DO:

• Within 48 hours of arrival*, sub-divide my delivery of fresh beans into 0.5L European canning jars which, when used to store coffee beans, are approximately 180 grams in capacity.
• On an "as needed" basis, I remove one container from the freezer and, leaving it sealed, set it on the granite kitchen counter; this is typically done the night before the beans are actually needed, so that the coffee can slowly come up to ambient temperature overnight.
• In the morning, I empty the 180 grams into the grinder's hopper. This will last from 1-2 days, thereby ensuring the beans are fresh.
• By following this technique, I have notice zero difference between beans ground straight from the bag (i.e.: never frozen) and those taken from the freezer.

WHAT I KNOW:

• A container of coffee beans -- or anything else, for that matter -- taken straight out of the freezer will quickly (if not immediately) be covered with condensation.
• Opening a frozen container -- versus one that has been allowed to come to ambient temperature -- will permit that condensation to form on the contents within said container.
• The longer that container is open and out of the freezer, the greater the condensation.
• Frozen anything is harder than room temperature anything.
• Coffee grinders are not designed to grind frozen anything.
• While freezing certain foodstuffs has been demonstrated to cause no significant loss of quality, freezing-and-refreezing any foodstuff is detrimental.

WHAT I THINK/BELIEVE/SUSPECT:

• Condensation on coffee beans is detrimental to their quality.
• Taking coffee beans "in and out" of the freezer is detrimental to their quality.
• Grinding frozen coffee beans is detrimental to the grinder.

30+ years ago, I used to freeze my coffee beans in 1.0-1.5L canning jars, and scoop out only what I needed to make my pot of drip coffee. I admit that if you rapidly "remove-scoop-refreeze," you can minimize the condensation, but I do not think you can eliminate it completely -- and if you do not replace the beans in the freezer "instantly," the more condensation will form on the beans in the open container.

Cheers,
Jason

* This varies with how fast the shipment arrives. Yesterday (Monday, Jan. 4th), I received a delivery from Caffè Fresco that I placed Saturday, Jan. 2nd. (Kudos to Caffè Fresco!!!) I'll break it down this evening.

I freeze my roasted coffee in Foodsaver vac bags & I see little if any condensation on the bag when I remove it from the freezer & leave it on the counter to warm up. Glass jars are another story entirely which is just one of the reasons I don't like to use them.

Normally I will allow the beans to come up to room temp before opening the bag but I have used them right out of the freezer several times. I've yet to see any condensation on the beans themselves when I've done this.

How much moisture is left in a roasted bean? Are they really frozen or just cold?

It seems to me that still-frozen beans are harder and more brittle, so more fines are created during grinding. This could easily be tested by freezing 2 jars of the same coffee, pulling one out the night before, and one the day of and pulling side-by-side shots to see if the cold coffee extracts more slowly. I have pulled shots from frozen coffee, but I haven't done an A/B comparison.

I freeze my coffee in airtight jelly jars filled to the brim to minimize airspace. I pull a jar out the night before to thaw before use.

One thing I enjoy when opening a thawed jar is that the coffee has degassed enough to build up a little pressure. When unscrewing the lid, the pressure releases and sweet coffee fragrance burps out.

JohnB. wrote:How much moisture is left in a roasted bean? Are they really frozen or just cold?

Just to be clear, condensation does not come from the bean, but from the atmosphere . . .

zin1953 wrote:Just to be clear, condensation does not come from the bean, but from the atmosphere . . .

I wasn't referring to the condensation when I asked about moisture content I was wondering how something(roasted coffee) with little or no moisture in it can be considered frozen.

It's a colloquial usage meaning "cooling something below the freezing point of water." There is moisture remaining in roasted beans, but I doubt it's at a level where it crystallizes.

Also see Frozen Food. The main thing with coffee is probably not taking away water from pathogens that rely on it for spoiling food, but is mainly just a generic slowing of the oxidation reactions that turn the oils rancid and turn the coffee bad.

shadowfax wrote:It's a colloquial usage meaning "cooling something below the freezing point of water." There is moisture remaining in roasted beans, but I doubt it's at a level where it crystallizes.

In the Professional Barista's Handbook Scott Rao references a 2007 study published in the Journal of Agricultural & Food Chemistry that found that the scant moisture in roasted coffee beans is bound to the matrix polymer, and therefore nonfreezable.

zin1953 wrote:Who grinds frozen beans?

Jason, your observations make sense. But I've watched Abe Carmeli dump frozen beans into his Versalab M3, and produce spectacularly good shots. I've occasionally ground frozen beans (when I didn't want to wait for them to thaw) with no ill effects.

zin1953 wrote:Who grinds frozen beans? As I've said, I take them out of the freezer and let the beans come to ambient temperature overnight. If you grind frozen beans, you get all sorts of condensation ON the beans -- and that's definitely not good!

Seeing as this reply was for me I should note that I don't make it a habit of grinding frozen beans but I do it on occasion when I don't have a thawed bag at the ready. I've found no difference other than needing to grind a touch coarser.

Given that roasted beans have no free water, they are probably not harder than room temperature beans. It may also mean they can be frozen and refrozen with relative impunity.

The problem of getting condensation on the grinder when grinding frozen beans is obviated because ground coffee will fairly rapidly absorb about 5% of their dry weigh in moisture. This may mean any condensate on the beans is absorbed by the ground coffee, rather than rusting the burrs.