I know this is an espresso site, but if you're ever bored, it would be interesting to apply the same study to another preparation method. With all the variables that go into properly preparing espresso, it's probably more challenging to find differences in the beans. Perhaps trying the frozen and unfrozen coffees in a "cupping" presentation, or even in a french press, might make it possible to zero in on some repeatable differences (if any).

ronpistolero wrote:Hi. Very interesting and helpful article indeed. This somehow gives me hope regarding "preserving" coffee. After having tried the Black Cat (best aroma and taste to my mind). I asked my brother to send another pound back here in the Philippines. He included a pound of Artigiano from Vancouver. I decided to "glad wrap" it, twice, in its original package without taping the valve, and keep it in the freezer. It was, I believe, 11 days old then. After having enjoyed the Artigiano, I thawed the Black Cat on the 21st day. I pulled a shot and, to my dismay, the aroma was nearly gone. It tasted like ordinary espresso (though not a "sink shot) to me. Could it be that I hadn't sealed it well enough? I haven't measured the temperature of my freezer, but could it be not cold enough? Was it too "old" prior to freezing? Having great tasting coffee is a rarity here in the Philippines so stretching the life of the ones I am able to acquire from abroad is very important to me. Help!

Ron

Of course I don't know the answer. 11 days out from the roast is getting a bit long in the tooth anyway; I've had black cat a number of times but never when it was that old. Also, the coffee may have been exposed to some extremes of temperature en route to you.

Is it possible for you to take up homeroasting?

ken

CGP4 wrote:I know this is an espresso site, but if you're ever bored, it would be interesting to apply the same study to another preparation method. With all the variables that go into properly preparing espresso, it's probably more challenging to find differences in the beans. Perhaps trying the frozen and unfrozen coffees in a "cupping" presentation, or even in a french press, might make it possible to zero in on some repeatable differences (if any).

Jim Schulman has done exactly this and his informal results are reported towards the end of the article. He says he could differentiate between fresh and previously frozen, but with no more accuracy than he could distinguish between two different roast batches of the same coffee, neither of which had ever been frozen.

I believe it is his opinion that freezing does not cause significant "damage" to coffee that is used for other things besides espresso.

ken
p.s. I don't think I could ever be so bored that I would want to do another study on freezing and coffee

Ken Fox wrote:Is it possible for you to take up homeroasting?

Hi Ken. Tell me how to roast a blend that I would be able to come close to how the black cat tastes like and I'll try it. Actually, a friend of mine gave me 100% Kona coffee and I tried roasting it. I did my very first batch via hot air gun to what I'd consider a light roast and I didn't like the taste. Too light, insignificant. (I'm really poor with adjectives). However, the next batch I did was very good. I "fried" the beans with the pan's glass cover on, constantly shaking the pan and "flipping" the beans as though they were pancakes. I did it until the beans were much darker, relatively lighter than the italian roast. It turned out to be very good.

You may remember that Versalab brought their M3 espresso machine to the Seattle SCAA show, but weren't able to produce very good espresso with it. At the time they (and Mark from Kaladi, the roaster) were severely castigated by some for using coffee that had been frozen. This is interesting, from Kaladi's website:

Freezing is one practice that sets Kaladi Brothers Coffee apart from other roasting companies. We place our beans in the freezer directly after roasting so the staling process does not begin before you, the customer, purchase our coffee.

Staling occurs at room temperature regardless of how coffee is packaged; packaging alone cannot preserve freshness. For maximum freshness, store your coffee in the freezer.

To protect your beans from moisture damage in the freezer, it is important to use an air-tight container such as a glass or ceramic jar. Studies show coffee stored this way can last up to a year or more!

You may grind your coffee frozen- direct from the freezer. There is no need to thaw the beans before grinding. A side benefit to this method is less build up on your coffee grinder.

They don't even thaw it out before grinding!

AndyS wrote:You may remember that Versalab brought their M3 espresso machine to the Seattle SCAA show, but weren't able to produce very good espresso with it. At the time they (and Mark from Kaladi, the roaster) were severely castigated by some for using coffee that had been frozen.

I think some us of were castigating more about the the coffee being roasted so dark that it tasted like a ten day old ashtray. On the other hand, I suppose it can pay to explore the market niche on the darker side of Starbucks.

another_jim wrote:I think some us of were castigating more about the the coffee being roasted so dark that it tasted like a ten day old ashtray

I didn't hear that, I guess there were multiple castigation modalities.

Ken,

That was a great deal of work my friend. I was impressed.

As I read through, (I admit I skimmed over here and there), I didn't notice any comment on refrigeration vs freezing. I buy my beans from Vivace, and get them either the same day they're roasted, or the following day. Schomer advocates refrigeration of purchased beans vs freezing. I do not recall why, but I believe it had to do with the potential of thawed beans gunking up the works of your grinder. Of course, for all I know, Schomer may have altered his opinion about this by now.

Anyway, I usually buy 3 lbs about every other week or so. I do see a deterioration in shot quality after a couple weeks or so in the refrigerator, but by then, a new order was on the way.

I guess if you're roasting and producing quantities that aren't going to be used up anytime soon, freezing may be a solution. I know that Montana Coffee Roasters advocate freezer storage. Whenever I have visited them, they stress that in spite of all the objections to this, that freezer storage is the best method of storage.

Rich

olypdd wrote:Ken,

That was a great deal of work my friend. I was impressed.

As I read through, (I admit I skimmed over here and there), I didn't notice any comment on refrigeration vs freezing. I buy my beans from Vivace, and get them either the same day they're roasted, or the following day. Schomer advocates refrigeration of purchased beans vs freezing. I do not recall why, but I believe it had to do with the potential of thawed beans gunking up the works of your grinder. Of course, for all I know, Schomer may have altered his opinion about this by now.

Anyway, I usually buy 3 lbs about every other week or so. I do see a deterioration in shot quality after a couple weeks or so in the refrigerator, but by then, a new order was on the way.

I guess if you're roasting and producing quantities that aren't going to be used up anytime soon, freezing may be a solution. I know that Montana Coffee Roasters advocate freezer storage. Whenever I have visited them, they stress that in spite of all the objections to this, that freezer storage is the best method of storage.

Rich

Rich,

My impression, based on nothing, is that the rate of degradation of coffee after roasting is a function of storage temperature. If this is true, it would indicate that sealed refrigerator storage will slow down the rate of aging vs. room temperature storage. I would be careful, however, to have the beans in a sealed vessel of some sort because refrigerators, unlike most freezers, are full of food based odors and you would not want those to be absorbed into the roasted beans.

I can't come up with a good reason why refrigerator storage would be preferable to freezer storage, since in the freezer you really have a lot more time to get to the beans and if for some reason you don't get to them quickly, they are still in there waiting for you to use them. With refrigerator storage I think you might extend the shelf life by some percentage, but deterioration would continue unabated. Since I've not tested this, and what's more have no experience with it myself, I can't go any further.

I think you will find that there is precious little, perhaps zero, data behind the strongly expressed opinions of some against freezing.

ken

First, a belated Kudos for a great job Ken!

It'll be nice to be able to just post a link instead saying the same thing over and over.

Ken Fox wrote:My impression, based on nothing, is that the rate of degradation of coffee after roasting is a function of storage temperature. If this is true, it would indicate that sealed refrigerator storage will slow down the rate of aging vs. room temperature storage. I would be careful, however, to have the beans in a sealed vessel of some sort because refrigerators, unlike most freezers, are full of food based odors and you would not want those to be absorbed into the roasted beans.

I can't come up with a good reason why refrigerator storage would be preferable to freezer storage, since in the freezer you really have a lot more time to get to the beans and if for some reason you don't get to them quickly, they are still in there waiting for you to use them. With refrigerator storage I think you might extend the shelf life by some percentage, but deterioration would continue unabated. Since I've not tested this, and what's more have no experience with it myself, I can't go any further.

I think you will find that there is precious little, perhaps zero, data behind the strongly expressed opinions of some against freezing.

ken

Wholeheartedly agree. Seems often those who strongly eschew freezing coffee have never actually tried it just "I heard"!

Also agree freezing much more effective than refrigeration. Not based on any scientific evaluation just in the cup and years ago at that. Even though freezing roasted coffee isn't for my normal consumption now, it was before I started home roasting 6 years ago. And I do still freeze some, especially to have an emergency roast supply on hand and for returning from trips. And I have pulled 75% plus crema shots of 6 month plus frozen roasts, oh and they tasted pretty darned good too. Maybe not as good as directly 5 days rest from roast, but not like even 2 weeks stored at room temperature either. With the added caveat mine are always vacuum sealed rather than just sealed.