Freezing ground coffee

[polly]

Does freezing ground coffee help it to stay fresh for longer? or is this a myth?

What is the best way to store freshly ground coffee?

[phaelon56]

Does freezing ground coffee help it to stay fresh for longer? or is this a myth?

In my opinion it's not a myth and I say that based on personal experience. There are limits to how long you can store it but it's still better than being stored at room temp if you're going to have coffee around the house for more than 10 - 14 days after its roast date.

But that brings up a crucial topic: freshness of the roasted beans themselves. If you can find a local roaster and buy beans on roast date or close to it (i.e. within a day or two of the beans having been roasted) it's highly advisable. Or find a good mail order source who ships fresh immediately after roasting.

Some pundits will decry freezing and insist that you must seek out and buy freshly roasted beans and never freeze. I get their point but for many people it's impractical and they just want to preserve as much quality as they can.

There was a terrific article that Ken Fox wrote recently for Home-Barista.com

Coffee: To Freeze or Not to Freeze

It actually has some fairly dense statistical analysis but the short version is that under reasonably well controlled conditions the autor and his testers/tasters could not find and significant difference between fresh and frozen/thawed coffee.

That's not to say there is no difference - I'm sure that extremely refined palates can taste a difference under some circumstances but people with that ability to discern extremely subtle nuances in coffee are not the typical home coffee drinker.

What is the best way to store freshly ground coffee?

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You really, really, REALLY need to consider buying a decent grinder, switching to whole bean coffee and grinding by the pot just before brewing. Freezing is still better than not freezing but if you absolutely must then portion out the freshly ground coffee into individual baggies and store those inside a freezer bag. An hour or more - or the previous evening before brewing - take out one bag that has just enough to brew one pot and let it thaw. This procedure prevents moisture from being sucked up by the remaining coffee when you open the freezer.

Even a cheap grinder (i.e. a $20 blade grinder or a $100 burr grinder - skip the cheap burr grinders) is the biggest possible bang for the buck that exists when it comes to imporving your coffee. That and buying freshly roasted that is stored (or frozen) properly.

[polly]

Wow, thanks Phaelon56 for all that info and the link.

I live near a shop that roasts every day so i have been buying ground from them but you write convincingly for the home grinder. It'll go on the list...

Thanks again

[scubadoo97]

You really, really, REALLY need to consider buying a decent grinder, switching to whole bean coffee and grinding by the pot just before brewing.

So true! This is one of the 1st steps you can take to better coffee.

[prasantrin]

If freezing whole beans is better than not freezing them (for longish term storage), what about already ground coffee? Is it OK to freeze it, too? I'm not really a coffee drinker, but sometimes I like to drink cafe au lait made with my mukka (maybe once a month). At present, I use Illy, but am planning to get some Intelligentsia when I'm in Chicago this summer, preground because I don't think I can grind for a moka maker with my blade grinder (which sucks, anyway).

[phaelon56]

If freezing whole beans is better than not freezing them (for longish term storage), what about already ground coffee?  Is it OK to freeze it, too?  I'm not really a coffee drinker, but sometimes I like to drink cafe au lait made with my mukka (maybe once a month).  At present, I use Illy, but am planning to get some Intelligentsia when I'm in Chicago this summer, preground because I don't think I can grind for a moka maker with my blade grinder (which sucks, anyway).

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The answer was hidden towards the end of my somewhat wordy post....

Freezing is still better than not freezing but if you absolutely must then portion out the freshly ground coffee into individual baggies and store those inside a freezer bag. An hour or more - or the previous evening before brewing - take out one bag that has just enough to brew one pot and let it thaw. This procedure prevents moisture from being sucked up by the remaining coffee when you open the freezer.

The biggest issue with freezing coffee is that every time you open the frozen container to take some out and then return it to the freezer the coffee you had in that opened container sucked up moisture when it was open briefly. Coffee loves to suck up moisture from the air but it's not a good thing in the cup.

So... whether it's whole bean or pre-ground -- bets bet is to freeze small portions in zip-loc sandwich bags and then put all of those in a freezer bag. Take out just the portion size bag that you'll use in a day or two and immediately return the main bag to the freezer. Allow the bag you're going to use to thaw for an hour or longer before opening.

And you're right that a cheap blade grinder won't produce a consistent enough grind for a moka pot or an espresso machine.

By the way - I actually freeze and periodically use a specific pre-ground coffee that I can only find locally in vacuum packed pre-ground form. It's the Vietnamese brand Trung Nguyen and I've yet to find any other coffee that makes nearly as good a cup of cafe sua da (Vietnamese style iced coffee).

[RobertCollins]

A friend of mine insists that storing my roasted coffee beans (or pre ground) in the freezer will make them only suitable for lining a stable floor. Something about the freezing causing the oils to be forever caught up in the grounds and not able to be released, according to him.

Frankly, I can't tell the difference. I do this on my boat because it may be weeks between visits that I grind and make a press full. If I just leave the beans in a container in the cupboard, it can be less than good even rancid. How does one store coffee long term?

The local Tully's Coffee tells us they want their coffee used within two weeks of roasting. That seems to me hard to do with any long supply chain to their sale points.

Edited May 2, 2009 by RobertCollins (log)

[Chris Hennes]

As near as I can tell, from a storage perspective with already-roasted coffee we are concerned with three things:

• Preventing the evaporation/dissipation of flavor compounds
  
• Preventing the oxidation of essential oils
  
• Preventing the absorption of other flavors/odors
  

For the first two, low-temperature storage is a no-brainer. Both processes (evaporation and oxidation) are temperature-dependent, and the lower the temperature the slower they occur. The third, preventing the absorption of off-flavors from other stuff in the freezer, is addressed by a) freezing whole beans rather than grounds (lower surface area on which to absorb anything, slowing down the absorption), b) storing in a tightly-sealed container, and c) store everything else in your freezer tightly-sealed as well.

From a physics standpoint I don't see how freezing beans could on its own decrease the release of flavor as you brew (provided the coffee is allowed to come back to room temperature before brewing). With most foods our concern when freezing is cell damage, but a roasted coffee bean's cells are about as "damaged" as they are going to get, and we're not worried about its texture anyway, so that would not seem to be the case here. What physical mechanism does your friend say is occurring to cause the flavor release to decrease?

[Richard Kilgore]

I agree with you, Robert.

As others here suggest, if I am not going to use my beans within a short period of time - usually within 10 days of roasting - I put one day's worth per one small zip lock. Then put all these daily ziplocks in a large ziplock and freeze them.

If you take out just the one daily bag and let it come to room temp before grinding it, it's difficult to tell a great deal of difference from freshly roasted beans.

[Jaymes]

If you take out just the one daily bag and let it come to room temp before grinding it, it's difficult to tell a great deal of difference from freshly roasted beans.

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Interesting that you put emphasis on letting the beans come to room temperature before grinding. The owner of a local coffee bean shop told me that one of his little tricks that he advises folks with those inexpensive home grinders to do is to grind the beans frozen. He said that the action of the whirling blade grinding the beans produces a lot of heat. And that in essence, you're heating the beans before you brew them, and that definitely hurts the flavor before you actually do the brewing.

So, according to him, unless you have one of those expensive grinders that doesn't have a whirling blade producing considerable friction heat, you should grind them frozen.

Everybody's got an opinion, right? And so often, they are in direct opposition. Impossible, sometimes I think, to really know what to do.

Edited May 2, 2009 by Jaymes (log)

[Richard Kilgore]

Interesting point you make, Jaymes. I should have qualified my comment to say I use a burr grinder. It may be that grinding beans in the frozen state works best for a blade grinder. An emprical question then.

Has anyone tried both methods with a blade grinder?

To the point of blade grinders overheating beans - one problem I have seen is people over grinding their beans - holding down the button for, say, 45 seconds.

[nakji]

Hmmm. I just got a kilo bag of coffee from my favourite roaster in Hanoi, Cafe Mai. I was going to save it for when I get back to Canada, lest my family disown me, and I've just had it sitting in my kitchen (staring at me; tempting me), but based on this:

For the first two, low-temperature storage is a no-brainer. Both processes (evaporation and oxidation) are temperature-dependent, and the lower the temperature the slower they occur. The third, preventing the absorption of off-flavors from other stuff in the freezer, is addressed by a) freezing whole beans rather than grounds (lower surface area on which to absorb anything, slowing down the absorption), b) storing in a tightly-sealed container, and c) store everything else in your freezer tightly-sealed as well.

I'm going to wedge that sucker into my freezer until I go. I had always heard that freezing did nothing, but now I see I should have been questioning that all along.

[MGLloyd]

I have been roasting my own coffee for about ten years now. Immediately upon cooling the beans, I put the whole beans into an air-tight glass clamp-top jar and put it into the freezer. I remove the jar from the freezer, measure out the beans into the grinder and then return the jar to the freezer. The beans are ground frozen in a burr grinder and I then brew the coffee or pull the espresso.

Years of empirical experience have taught me that using this storage method, my beans stay fresh for two weeks. I generally cannot tell any taste difference between day 1 and day 14, except for the normal changes that come as a roast improves to about day 3 or 4.

The absolutely worst way to store coffee is to store ground coffee in a bag in the refrigerator. It rapidly picks up air, moisture and other odors and tastes from the fridge.

[Rob_T]

I might be a little anal here or..... I vacuum seal my roasted beans and then put them in the freezer.

I tend to get out a couple of days worth of whole beans for an airtight jar in the fridge. THe only problem I have is that the vacuum seal canister I use isn't designed for the freezer and sometimes it will "freeze" shut. It can be very very frustrating needing a cup of coffee that is hermetically sealed and isn't cooperating.

It has been a while since I did my own empirical research or kept beans long enough to matter but as I recall I have kept beans for several weeks without any noticable flavor change.

[barrett]

He said that the action of the whirling blade grinding the beans produces a lot of heat.  And that in essence, you're heating the beans before you brew them, and that definitely hurts the flavor before you actually do the brewing.

So, according to him, unless you have one of those expensive grinders that doesn't have a whirling blade producing considerable friction heat, you should grind them frozen.

Everybody's got an opinion, right?  And so often, they are in direct opposition.  Impossible, sometimes I think, to really know what to do.

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All grinders produce heat - you're taking beans and shaving them (with burrs) or pulverizing them (with blades) - where heat becomes an issue is for commercial operations who have their grinders running near constant throughout the day.

The first step to quality is grinding fresh. Fresh = now.

The second step is a quality grinder that you can actually control particle size with. Blades smash the coffee repeatedly, so within your sample, you have everything from sizeable chunks to powder - with burrs, the coffee is pushed out after it's ground, so it's only ground once, and there is a much tighter control over the size of particles.

Why does particle size matter? Because we want an even extraction. To coarse will end up with a weak brew, and too fine results in bitter, overextracted coffee.

I have been flirting with the idea of buying a home roaster.  I hear green beans will last close to forever.  Can you tell me more about roasting at home?

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Technically, they *can* last a long time, but you will get diminishing returns. As they sit, the moisture levels will change - plus any number of unknowns that have previously been ignored by roasters. Slowly, more and more roasters are getting on the idea of seasonality, and trying to minimize the time green is spending on the shelf.

[MGLloyd]

Technically, they *can* last a long time, but you will get diminishing returns. As they sit, the moisture levels will change - plus any number of unknowns that have previously been ignored by roasters. Slowly, more and more roasters are getting on the idea of seasonality, and trying to minimize the time green is spending on the shelf.

George Howell, of Terroir Coffee, is doing some interesting work in vacuum-packing and then freezing green beans. He believes that this maintains freshness of the green beans. I believe the jury may still be out as to if anyone else is using this method and believes it offers advantages in green bean storage.

[barrett]

Technically, they *can* last a long time, but you will get diminishing returns. As they sit, the moisture levels will change - plus any number of unknowns that have previously been ignored by roasters. Slowly, more and more roasters are getting on the idea of seasonality, and trying to minimize the time green is spending on the shelf.

George Howell, of Terroir Coffee, is doing some interesting work in vacuum-packing and then freezing green beans. He believes that this maintains freshness of the green beans. I believe the jury may still be out as to if anyone else is using this method and believes it offers advantages in green bean storage.

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Yes, he has been doing it for a number of years, we've only been doing it for 3 years or so, I think.

[MGLloyd]

Yes, he has been doing it for a number of years, we've only been doing it for 3 years or so, I think.

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So what do you and your customers think so far about the value of freezing green? Are there perceptible taste differences that cannot be ascribed to other variables of roasting, brewed coffee or espresso preparation?

Edited May 6, 2009 by MGLloyd (log)

[barrett]

mixed results.

for the best, consistent results, go with fresh crop.