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Guest Post

Freezing Green Coffee is a Game-Changer

Freezing roasted coffee is starting to become accepted. But what about the green beans?

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Guest Contributor

The article below is written by Scott Pardee, who is an avid home coffee roaster.

Initally, Scott wrote this as a response on The Coffee Chronicler’s Facebook page. However, I thought this post deserved a wider audience,  so I got his permission to publish it here as well.

Please note, that I haven’t personally experimented with freezing green coffee myself (yet), but at the moment I’m doing many promising experiments when it comes to freezing vacuum-packed roasted beans. 

Freezing roasted coffee is something the community has been very sceptical about in the past, but it seems like all this has changed the last couple of years.

If you’re a home roaster I encourage you to try the same experiment as the author, and decide for yourself whether it’s worth making a part of your coffee routine. And now I’ll give the word to Scott.

– TCC  

The argument is over. Freezing green coffee beans in vacuum-sealed bags is a vastly superior way to preserve the flavor of your favorite green coffee.

Let me explain how I did it, and why I think this method could be a game-changer for all roasters out there – both home-roasters and professionals.

In August 2019, I ordered 20 pounds of dry processed Kayon Mountain Ethiopian from Sweet Maria’s (cupping score 92). I got 20 pounds because it was an amazingly fruity coffee that instantly became one of the best-tasting coffees I have ever had.

In January of this year, I put 10 pounds in 20 eight-ounce bags and put it in the deep freezer. The coffee was five months old at the time of freezing.

Fast forward to this week. I still had 2 pounds left of the original (unfrozen) bag of Kayon Mountain. It is now one year and three months old).

I noticed that it didn’t taste nearly as good as the Hamasho village natural Ethiopian I had just got from Sweet Maria’s (cupping score 93).

The new one reminded me of why I liked the old one so much. But the fantastic flavors from the Kayon had receded noticeably, which only became evident when comparing it directly to a very fresh coffee like the Hamasho village.

The Kayon Mountain didn’t taste bad or anything, but the WOW! was gone. It had been stored in the original zip-lock bag in the dark cardboard box at room temperature.

Freezing roasted, vaccum-packed coffee has become popular in recent years. But what about freezing the greens?

The experiment that convinced me

Now, I expect to hear, “you can’t compare two different crops from two different places in Ethiopia; they aren’t the same coffee.”

That is technically true. But having roasted and drunk both coffees, I can easily state that the similarity is remarkable. They are both high quality, natural processed Sidamo coffees.

But I’m not done yet. Remember, I had previously frozen some of the Kayon Mountain coffee. In one sitting, I roasted three batches:

  1. Original Kayon (unfrozen)
  2. Frozen Kayon (thawed while still under vacuum)
  3. Hamasho Village

The results were obvious! The frozen Kayon blew away the unfrozen Kayon.

Keep in mind, both of these batches are the same beans that came in the same bag; the only difference is that one was frozen. That great fruity taste that I had remembered was suddenly back.

freezing vacuum packed green coffee
The beans are vacuum packed, so moisture is kept out.

And how did the frozen Kayon stack up to the newly received Hamasho Village? I would have to give the edge to the Hamasho, but not by much.

And I didn’t freeze the Kayon until it was already five months old. Needless to say, I will be freezing a bunch of the Hamasho Village this week while it is only two months old.

Frozen or fresh?

Home roasters go to great lengths to fine-tune all the many roasting and brewing aspects to get the best tasting cup of Joe.

I mean, it gets down to tiny minutia like:

Finding the perfect gooseneck kettle, the ideal brewing temperature, or whether Hario’s filters have gone downhill. Or endless tweaking of a roast profile. And the list goes on and on.

However, my point of view is clear: It all starts with the beans. And if they aren’t at their absolute best, nothing can be done to fix that.

Personally, I believe that vacuum-sealed freezing pretty much stops the bean degradation in its tracks and preserves the maximum possible quality.

TCC’s note: This has also been stated by coffee scientist Christopher Hendon. His theory is that most processes are slowed down significantly in the freezer — around half the rate by every 10 ºC something is cooled down. And some processes simply won’t be able to start at minus degrees.

Bean quality loss starts the second you get the beans, no matter how you store them (earlier if they didn’t just arrive at your favorite supplier).

How long is coffee still fresh? Give it whatever date you want, but it is less fresh with each passing day. It is not a “good one day, bad the next” type of thing. It is a sliding scale downward and how quickly depends on the storage method.

And for those who say green beans stay fresh for a year, I say BS. Drinkable, sure, but fresh, no.

I don’t think it stays at its peak for very long at all, maybe a few months.

Continued degradation after we get delivery is on us. Why would we go to all those extremes to roast and brew the best coffee only to fall at the finish line with less than the best-preserved bean? Huh?

An argument for freezing

I expect to hear someone say, “don’t order more than you will roast within a reasonable time, and you won’t have that problem and won’t have to worry about longer-term storage.” I think that misses several essential points.

  1. Scarcity of great greens: Great crops don’t grow on trees. Well, actually, they do, but you get the point. They are the result of a lot of things coming together perfectly to make a fantastic coffee. Nobody can snap their fingers and duplicate it. We all remember a truly great bag of beans that we were unable ever to find again. Not even from the same farm by the same farmer from the same supplier.
  2. Harvest season & export: To use the Ethiopian example, it is not possible to get “new” totally fresh beans in February. The beans have already been sitting in warehouses and containers for around six months. This will be true for all coffees everywhere, depending on a given country’s harvest time and international logistics. So, if you don’t order a sizeable quantity of that excellent bean you discovered, then you have to wait a whole year for the next crop. And there is no guarantee that the quality will be the same.

Final words

I didn’t invent this method; as far as I know, George Howell or somebody from his company began doing it all the way back in 200o’s. There is not a lot of information from him about the results. But it must work because he uses freezing as a way to compare one year’s harvest to another year.

You couldn’t do that if freezing didn’t preserve the exact taste. He also now sells coffee that has been frozen. That says it all. Why would you go to all that extra cost and work if it didn’t truly help preserve flavor better than the usual storage methods?

A cheap vacuum-sealer and a roll of bags are very affordable on Amazon. No need at all for an expensive machine.

Having tried this method and being very satisfied with its efficacy, I can now roast my favorite coffees with no loss of quality any time I want for years. To me, that is a step forward in coffee quality that’s superior to all the small brewing hacks and incremental advantages that we usually talk about.

Top Featured Image: Michael Coghlan – Flickr CC