Freezing Coffee, good or bad?

[OldSaw]

My wife likes to buy bulk coffee from a local roaster and put the bags in the freezer. I say it ruins the taste and dries it out. So one day while at the shop she asked a clerk, (clearly a minimally trained part time worker), and she said she freezes coffee all the time. My wife almost took that as gospel but also came to the realization that the clerk wasn't the brightest bulb in the box.

As additional information, my wife likes to especially do this with a seasonal blend, so she can have it all year. So what is the consensus among the coffee crowd?

[JBHoren]

My wife likes to buy bulk coffee from a local roaster and put the bags in the freezer. I say it ruins the taste and dries it out. So one day while at the shop she asked a clerk, (clearly a minimally trained part time worker), and she said she freezes coffee all the time. My wife almost took that as gospel but also came to the realization that the clerk wasn't the brightest bulb in the box.

As additional information, my wife likes to especially do this with a seasonal blend, so she can have it all year. So what is the consensus among the coffee crowd?

Freezing coffee beans (as well as storing them in the refrigerator) ruins the taste of roasted beans, and destroys green beans.

I also buy in bulk, and what I do is to store green coffee beans in vacuum-sealed, 1-quart Mason jars (I bought a Foodsaver unit on eBay); I also store roasted coffee beans in the same-size Mason jars, but without the vacuum-sealing (doh!)

Is your wife's "seasonal blend" pre- or post-roast? I never roast in larger-than 1-quart quantities, preferring to roast anew when the need arises.

[RichGem]

Freezing coffee beans (as well as storing them in the refrigerator) ruins the taste of roasted beans, and destroys green beans.

I also buy in bulk, and what I do is to store green coffee beans in vacuum-sealed, 1-quart Mason jars (I bought a Foodsaver unit on eBay); I also store roasted coffee beans in the same-size Mason jars, but without the vacuum-sealing (doh!)

Is your wife's "seasonal blend" pre- or post-roast? I never roast in larger-than 1-quart quantities, preferring to roast anew when the need arises.

'

Why no vacuum seal on the roasted beans? Is it just not necessary, or is there some other reason?

[OldSaw]

Freezing coffee beans (as well as storing them in the refrigerator) ruins the taste of roasted beans, and destroys green beans.

I also buy in bulk, and what I do is to store green coffee beans in vacuum-sealed, 1-quart Mason jars (I bought a Foodsaver unit on eBay); I also store roasted coffee beans in the same-size Mason jars, but without the vacuum-sealing (doh!)

Is your wife's "seasonal blend" pre- or post-roast? I never roast in larger-than 1-quart quantities, preferring to roast anew when the need arises.

Post roast.

[Aevum]

freezing anything which is plant or animal damages cell structure, crystalization of water damages the structure.

[JBHoren]

'

Why no vacuum seal on the roasted beans? Is it just not necessary, or is there some other reason?

An excellent question!

1. Newly-roasted beans "out-gas" CO₂, so a vacuum seal would prevent its venting; and
2. Every time you opened the jar, you'd "break vacuum" and have to re-seal afterward.

Even a month after roasting, my coffee beans continue to "out-gas" CO₂; since I store them in Mason jars with the vacuum-seal lid, the greater pressure inside the jar causes quite a pop! when I open one to fix my morning brew.

Hope this helps!

[sehrgut]

Freezing has its uses; however, you have to be careful. First, ensure that you're freezing in airtight containers. Second, freeze in amounts that can be used up in two weeks. Third, only ever freeze once (to avoid condensation).

Now, for the bad news. Even frozen, coffee still stales: it just does so at a slower rate (chemical reactions still happen, just not as quickly). You can consider coffee that was frozen a couple of days post-roast (to allow for some outgassing) to be good up to three months later, but that's pushing it. Also, re-freezing will likely (as I alluded to earlier) permit condensation, which is the death knell.

So: assuming you've frozen coffee in two-week "supplies", remove one from the freezer and store it airtight at room temperature while using it for the next two weeks. Then take the next one and do the same. For the next three months. Then give whatever's left over to someone who drinks Folgers: they won't know the difference.

[sehrgut]

freezing anything which is plant or animal damages cell structure, crystalization of water damages the structure.

Roasting damages cell structure. If you look at a micrograph of pre- and post-roast coffee (sorry, I don't seem to be able to find the ones to which I normally refer), you'll see that roasted coffee has little to no intact cellular structure.

As well, roasted coffee is so low in water content that crystal formation is unlikely in any case.

[apswartz]

If you Google the question and check the coffee sites you will see that there is no unanimous opinion on this subject

[JBHoren]

Is your wife's "seasonal blend" pre- or post-roast? I never roast in larger-than 1-quart quantities, preferring to roast anew when the need arises.

Post roast.

My Foodsaver unit has an attachment for wide-mouth Mason jars (you can buy them online from Ace Hardware), and it works very well. In fact, they promise a shelf-life of much longer than one year.

OTOH, if you vacuum-seal the newly-roasted beans, their "out-gassing" will create quite a lot of positive pressure inside that jar...

My choice would be to blend and vacuum-seal the green coffee beans, and roast a 1-quart jar's-worth; roast more, when needed.

[uofi1963]

Some of the mavens at home-barista.com have posted in detail on this issue. The general consensus was that freezing in airtight bags for roasted beans was the best way to maintain freshness.

Old Joel

[Monkeyboy]

I respect Mark Prince's opinions in the ways of coffee. He states that freezing coffee immediately after roasting will keep it fresher if you are storing for weeks to months (I guess he did some blind testing). But it still won't be as good as it was fresh. Keeping coffee air-tight, at room temp, and brewing within 7-10 days after roasting is absolutely ideal.

I found some great containers put out by the makers of the vacuvin wine stoppers. They use the same pump to create a vacuum and are tinted to help keep light out.

As for a solution to enjoying that blend year round? Roast it yourself. Most roasters don't object to selling you their green beans and usually do so for 25-50% less than roasted beans.

[Suzuki]

I'm no expert, but my personal experience is:

1) Fresh roasted is best - the fresher the better and there's no substitute/method of storing that keeps roast coffee tasting the way it did when it was fresh.

2) I've found that, for relatively short term storage (couple of months) storage in a cool dark environment (as in a kitchen drawer that isn't next to the oven) in an air-tight container is better than the freezer.

I can generally taste when beans have been frozen - they just don't have the snap/zip.

All this being said, I don't buy my coffee in bulk and don't recommend it to anyone who has access to good freshly roasted coffee. If you don't have access to this, buy your coffee from a store with good turnover, so that whatever you get is as fresh as possible and only buy what you need for a week or two.

Finally, beans always stay fresher than ground - so if you're going to store coffee for extended periods, stick with the beans.

[Scotto]

Here's your answer:

Vacuum sealed and frozen beans for long term storage seems to have some evidence behind it. However, if you are talking about tossing beans in the freezer (or refrigerator) and grabbing some every day for your morning brew, that is a strict no-no. The cycling of temperature back and forth causes moisture to condense on the beans, killing them even faster.

Your best bet is to not buy in bulk at all; coffee stales in days after roasting. Store what you need for a week or two in an airtight container at room temperature.

[OldSaw]

Here's your answer:

Vacuum sealed and frozen beans for long term storage seems to have some evidence behind it. However, if you are talking about tossing beans in the freezer (or refrigerator) and grabbing some every day for your morning brew, that is a strict no-no. The cycling of temperature back and forth causes moisture to condense on the beans, killing them even faster.

Your best bet is to not buy in bulk at all; coffee stales in days after roasting. Store what you need for a week or two in an airtight container at room temperature.

Thanks for summing this up for me Scotto. That seems to answer my question pretty well. I have no desire to roast my own at present. I also did notice a significant difference in taste from the sealed bags that the shop packed the beans in and the paper bags my wife filled herself.

Like I said earlier, this is a seasonal blend that she is trying to keep all year. I personally get tired of it after a while and don't mind waiting until the next season.

[Howard Newell]

Roasting damages cell structure. If you look at a micrograph of pre- and post-roast coffee (sorry, I don't seem to be able to find the ones to which I normally refer), you'll see that roasted coffee has little to no intact cellular structure.

As well, roasted coffee is so low in water content that crystal formation is unlikely in any case.

I think you mean the actual cellulose structure of the bean. The majority of the actual 'bean' is just the endosperm which serves as food for the developing embryo. There would actually be very few cells in the coffee bean at all, either in the form of a cell that has the normal number of chromosomes or a clump of cells that arrest at an early development.

[Lynchmeister]

Great topic! I'm afraid my wife and I are guilty as charged on all accounts. Buying more than a week's worth, storing in ziploc bags in the freezer, and accessing the bag daily for the morning brew. In our defense, we do grind "to order," but it's a blade grinder.

I will halt this practice immediately, buy no more than a week's worth at time, and store in tightly sealed (sans vaccuum) Mason jars with the rubberized seal.

[profsaffel]

I consider my father a somewhat connoisseur of coffee - he's been drinking the stuff for 35 plus years, he introduced me to the concept of grinding your own beans, and he puts coffee right next to wild game on his food pyramid.

And he swears by refrigerating the coffee to maintain freshness. I agree wholeheartedly that freezing and thawing is not good for your coffee, and I doubt refrigerating is better of less-than-three day old coffee grounds, but I can agree with the ol' man that fridging the coffee does at least keep it somewhat more moist than not doing it.

Not science, just an observation.

[sehrgut]

I think you mean the actual cellulose structure of the bean. The majority of the actual 'bean' is just the endosperm which serves as food for the developing embryo. There would actually be very few cells in the coffee bean at all, either in the form of a cell that has the normal number of chromosomes or a clump of cells that arrest at an early development.

Yes. However, that "cellulose structure" is cell walls. Endosperm is a cellular tissue. In most angiosperms (and thus, I would guess, coffee as well), endosperm forms as a large syncytium (mass of divided cells that have not formed walls between them), and cell walls develop to divide it up later. Regardless, endosperm is cellular in structure.

[sehrgut]

but I can agree with the ol' man that fridging the coffee does at least keep it somewhat more moist than not doing it.

Coffee should not be "moist". Moisture allows hydrolytic reactions causing early breakdown of flavour. While refrigeration will prevent oxidation (and thus bittering), it will in most cases actually accelerate the staling process.