I'm not much of a taste-tester, and I've recently been posting on the pitfalls of "The Science of Coffee". That said, I went with Ken's suggestion to freeze coffee, since I have no other choice at present. I've been getting two pounds a month of fresh beans, and popping them in the freezer. I open them daily, take out the daily ration and just squeeze the air out of the foil bag and seal it with rubberbands. The results have EXCEEDED my expectations, in that I still get good crema and flavor at the end of the month. In fact, I once got two bags that I suspect were older (couple weeks?) on arrival. The fresh beans I had frozen for a month were better than the older beans when they arrived.

Just subjective observations, but freezing seems to do the job for me here on the last frontier.

PC

I have squirreled away two pounds of coffee into the freezer to see how long I could push the envelope. I do not have any fresh coffee to compare my frozen samples with since one pound was from Rocket and the other Caffe Fresco (both no longer roasting).

The pound of Rocket I put in a one quart mason jar, filled to the top and put a fresh seal and ring on the jar to make sure it is air tight. The ambrosia from Fresco I left in the pound valve bag and taped over the one way valve to prevent it from gassing in, or out. I labeled both with the roast date (June for the Rocket and July for the Fresco) and tossed them into the back of my deep freezer (-15F).

Let me start by saying that freezing will slow the degradation of the coffee, but not stop it. A fact that is evident in the pressurized jar and valve bag that blew up to pillow proportions. Both coffees continued to outgas and age.

Since I had stashed the Rocket in a mason jar that could be resealed, I opened it after two months and removed half of the blend, resealed the jar and returned it to the freezer within moments so the beans would not unthaw. I allowed the beans to unthaw for a day while sealed in a half pound valve bag. I was surprised at how well they weathered. The crema was thick and rich at 90+% of the shot. The taste appeared to be no worse for wear. I finished off that sample within 3 days with little change in flavor.

After another month, I retrieved the other half of the Rocket sample and allowed it to unthaw in the closed mason jar. Again, I was greeted with a Pop! When I loosened the ring, the frozen beans had continued to degas. This time I drug out the sample for 5 days. As with the original sample the initial results were on par with the first sample, good crema and flavor but the more delicate high notes and acidity appeared to be slightly muted. Over the next couple of days the beans appeared to hold their own, but on day 3-5 they fell flat. The beans suddenly staled and lost their entire nuance, in one day they went from not to bad to compost. I also noticed that I had started with a finer than normal grind on the second sample. That is another sign of beans that are reaching the end of their prime.

Yesterday, I pulled my jumbo swollen pillow sized pound of Ambrosia from the freezer, removed the tape that had been sealing the one way valve and was greeted with a stream of cold coffee scented air as the bag degassed. This morning I opened the bag and put half of it in the LaCimbali Jr grinder. Again, the beans are starting out with little degradation. I am getting nice tiger striping and flecking in the cup. The coffee is sweet and flavorful, much like I remember the blend being when fresh from the roaster. Over the next few days I will see how the blend holds up and if it also suffers from a sudden stale and loss of flavor.

Another key note here, these were pro roasted coffees that were shipped to my home so they had 3-4 days post roast on them before I froze them and not uber fresh from the roaster beans that were promptly frozen as Ken originally did.

My experiences in freezing are pretty much as you have just described. I have frozen several espresso bound blends from CCC and Ecco Caffe over the past year. I don't think I have gone past two months of freeze time on any of the occasions. The frozen beans tend to represent an in cup character nearly identical to the fresh unfrozen counterparts, but as you, I experienced a point where they degraded quickly (or so it seemed to me). One thing I did differently though, unless I am misinterpreting your post, was that I didn't expose them to ambient air until hours later when the beans were assumed to be thawed. Also, once they were out of the freezer, they didn't go back in. My reasoning for those two actions was to minimize any potential condensation. However, it sounds like the beans in the mason jar did great without taking such an approach.

You are reading correctly. However, the sample in the jar was opened but not allowed to thaw while I retrieved a half pound for testing, the resealed and returned to the chill chest. The second sample was allowed to thaw in the jar prior to opening. The Fresco was kept in the valve bag and not opened until a day after it was retrieved from the freezer, giving it ample time to unthaw while shielded from any condensation.

The Fresco is still holding its own after the second day from the freezer. As I mentioned, these were shipped samples so when I get to day 5 in use, the beans had another 3-4 days post roast on them before freezing. So at day 5 they are effectively 8-10 days out of the roast if you do not count the 4 months they were in the deep freeze.

Well, it happened today, my last quarter pound of Ambrosia fell flat on its face. It appears that coffee that is roasted then sits for a few days prior to being frozen suffers a very quick death. For the first couple of days it held up quite well with little degradation, day three I noticed a change in the cup, day four it is compost. It still pulls a visually appealing shot but all the sweetness and acidity is gone leaving you with a very generic "coffee" flavor.

For shorter freeze periods my samples have held up quite well. I have ordered two pounds, froze one and used the other. A week later retrieve the frozen pound and it lasts just as long as the fresh pound before it. After four months in the freezer, both of my samples had a 3 day lifespan before the flavor turned from bright and fruity to wet cardboard.

cannonfodder wrote:Well, it happened today, my last quarter pound of Ambrosia fell flat on its face. It appears that coffee that is roasted then sits for a few days prior to being frozen suffers a very quick death. For the first couple of days it held up quite well with little degradation, day three I noticed a change in the cup, day four it is compost. It still pulls a visually appealing shot but all the sweetness and acidity is gone leaving you with a very generic "coffee" flavor.

For shorter freeze periods my samples have held up quite well. I have ordered two pounds, froze one and used the other. A week later retrieve the frozen pound and it lasts just as long as the fresh pound before it goes stale. After four months in the freezer, both of my samples had a 3 day lifespan before the flavor turned from bright and fruity to wet cardboard.

These are all useful observations and I thank you for posting them, Dave. Although I have a small amount of experience freezing already-degassed coffee, my experience is overwhelmingly with coffee just out of the roaster. Even with "absolutely fresh" coffee frozen just out of the cooling tray, I never freeze more in a container than I can consume in a week. On those few occasions where I have had defrosted coffee lying around longer than a week (and sometimes less than a week, depending on the coffee) I start using it exclusively in milk drinks where whatever deficiencies as may develop are hidden. I've done this with botched roasts as well, ones that aren't quite bad enough to give to a friend of mine who will drink "anything" if it is free.

My freezing results are very good, but they are done with nearly ideal conditions, e.g. very cold chest freezers, nearly airtight jars, and with coffee just out of the roaster. For those buying already roasted coffee in bulk, that has significantly degassed when they receive it, I think it may make sense to freeze what is to be frozen in small batches, maybe even as little as 125 or 150g, so that it can be used up very quickly and the next bag then opened to continue using the stash. I have some small reused salad dressing jars (straight sided, for the kind of refrigerated salad dressings you can buy at a grocery store, like the "Lighthouse" and I believe the "Marie's" brands) that hold around this small quantity, and use them often to freeze small batches.

ken

Your testing was much more exacting than mine although I tried to be as open minded as I could, no blind tasting. One major difference between Kens testing and my little "lets see what happen" is the type of coffee. While Ken used freshly roasted I used artisan roasted and shipped so my beans already had some age on them.

I would agree with you small batch freezing. In both of my sample lots the coffee held up well for the first couple of days. So if you broke the batch size down to what you consume in a two day span, chances are that you would notice very little change before you have consumed the batch.

This is to notify readers of this thread and this article, that the original study has been repeated in March 2009, extending the results in several ways:

(1) a new taster -- Jim Schulman

(2) different coffee

(3) different dosing -- 14g; rather than 18-20 g as in the original study.

(4) different grinders, using hybrid conical/planar Cimbali Max grinders

(5) longer interval of freezing -- 3 3/4 month, as well as one month

(6) including a cupping component, in addition to blind tasting of espresso shot pairs

Results were, however, essentially the same.

Here's the link:

http://www.home-barista.com/tips/...rt-two-t10301.html

I probably would not have tried freezing my coffee if not for the research you have done and shared, Ken - so thanks.

It has changed the way I buy coffee. Now, I go to my roasters/resellers and buy 5lbs at a time, rather than mail ordering in 2lb amounts. Without exception, the salesperson asks how I can drink that much coffee before it goes stale. And without exception, when I tell them that I freeze it and pull it out 1lb at a time, they make a sour face and tell me that is not recommended.

The helpful person at a shop that gets Intelligentsia coffees flown in every week assured me that Intelly does not endorse or recommend freezing their coffee. Even after explaining that I seal it, freeze it only once, and thaw it in its sealed wrapper before opening, he could not be swayed.

I think the outdated notion of keeping coffee in the freezer between uses has made the whole idea of freezing coffee a difficult one to accept.

Mark

Dogshot wrote:The helpful person at a shop that gets Intelligentsia coffees flown in every week assured me that Intelly does not endorse or recommend freezing their coffee. Even after explaining that I seal it, freeze it only once, and thaw it in its sealed wrapper before opening, he could not be swayed.

Mark

There is a lot of resistance to the idea, among those who have good, fresh, coffee to sell, and among those who think they have good coffee to sell

I'm in Vancouver right now and a couple of days ago I got into a conversation about freezing with a barista at one of the better shops here. I described the experiments we have done and he told me that they couldn't possibly be conclusive without having many more tasters and hundreds or thousands of shot pairs to compare.

I told him that I agreed with him, in that there is no way that studies such as we have done could possibly detect very small differences that might be present, that could only become apparent were one to repeat the shot pairs hundreds or even thousands of times. Of course, there are many other major variables with the whole process of making espresso; everything from those among different roast batches of coffee to the ubiquitous intershot variations that are undeniable. What we have shown, however, is that whatever deleterious effects that freezing might have on coffee, are going to become lost among the other uncontrollable variables that go into espresso shot preparation for most people in most places.

At this point, as has been pointed out by Jim Schulman in the writeup of the original article, it simply doesn't cut it for a critic of freezing to say that freezing "damages coffee" without giving some sort of proof of that statement. We have done everything that we could reasonably do to try to find differences, detrimental or otherwise, that are imparted to coffee by the freezing process when that coffee is then used to make espresso (or the same coffee is cupped, as in the 2nd study). We have not found any evidence of damage, and in fact we have found considerable evidence that freezing, done properly, preserves and extends the shelf life of fresh coffee. Numerous people whom I personally respect have used freezing to extend shelf life, and have written about their positive experiences on this and other threads on this website. I have not read a single convincing post about a negative experience with freezing done properly, by anyone who clearly gave freezing an honest try (short posts without details obviously excluded).

To those who see flaws in the methodology we have used in these studies, I would encourage them to perform another reasonable, blind tasting study, to answer the same questions we have attempted to answer. We would all be interested to read about another blinded experiment testing the impact of freezing, especially if it reached a different conclusion. No one has a monopoly on "truth," certainly not us. However, simply repeating the same old biases (against freezing) with no proof whatsoever, does not reflect well on the ability of those making such statements to think for themselves or to absorb new information as the "science" of coffee "advances" over time.

ken