Should you freeze your coffee beans?

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On Aug. 19, I roasted some coffee for a friend and I gave it to her in whole beans. I told her to grind right before brewing for the best taste. She told me that her grinder wasn’t working, and that she'd put a new one on order, and asked if it would be OK to freeze the beans until she was ready to brew.

I’ve heard advocates for both sides of the argument. There are many against freezing coffee beans, believing that the moisture destroys the flavor. Others conclude that there’s no harm done. I told my friend to just keep it in the sealed bag I put it in and place it in a cupboard.

Then it dawned on me: What if freezing coffee beans would have been better, and I was giving my friend the wrong advice? The truth is, I roast or buy only enough coffee to last me a week or so — two weeks, tops — so I’ve never really had to store my coffee long-term.

That’s why I set out to do this experiment. Next time, I’ll have first-hand experience when I give my advice.

Roast and Storage:

On my next roasting day, I roasted an extra 8-ounce batch of Ethiopian Yirgacheffe to set aside for this experiment. I wanted to treat my “specimens” as identically as I could, so I placed one 4-ounce container of beans in the freezer (0°F) and the other 4-ounce container in the cupboard (70°F). I roasted them at medium/city roast — it’s the roast my husband and I prefer — right before the second crack.

Finally, to set a baseline, I brewed a fresh batch and took notes of the coffee's characteristics within 24 hours of roasting:

Brew before storage:

Fragrance (beans/ground): Blueberry tone
Aroma (brewed): Fruity tone
Taste: Hints of blueberry
Acidity: Some acidity/tang in flavor
Body: Light body
Aftertaste: None noticeable
Verdict: Love the smell and taste with blueberry tones!
 
I allowed the roasts to de-gas for at least eight hours. (Coffee beans release carbon dioxide soon after roasting and if you put them in an airtight container without a valve to de-gas, that container might explode from all the CO2 being released.) I didn’t have any extra airtight jars, so to make sure they didn’t get exposure to air, moisture, heat, and light I placed them (separately) in Ziploc sandwich bags, then grocery bags, and finally gallon Ziploc bags.

My original plan was to leave them in the freezer and cupboard for four weeks at the most, but I didn’t have the time to sit down to enjoy doing the experiment until almost six weeks later. 

The Brew

I originally thought my freezer specimen would taste, and be preserved, better than my cupboard specimen. As my husband pointed out, we freeze and thaw other foods, and they’re good as new as opposed to molding over time spent sitting in the cupboard.

At 8 p.m., Sept. 28, I took my specimen out of the freezer and let it thaw for at least 15 minutes before grinding it at room temperature, and took the other from the cupboard. Then, for each of my two specimens, I separated 30 grams to use for brewing, coarse-ground the beans, and heated 20 ounces of water to 195°F. I opted to use the pour-over method to easily observe the bloom when hot water hits freshly ground coffee, causing the bed of grounds to noticeably puff up, and used a brew time of four minutes.

I noticed that my freezer specimen had a larger bloom in comparison to the other, which may indicate that my cupboard specimen’s container may not have been airtight (or that my initial pour was not as good).

Ethiopian Yirgacheffe roast and brew: Cupboard sample (right), freezer sample (left). - ANGELA GREENBERG
  • Angela Greenberg
  • Ethiopian Yirgacheffe roast and brew: Cupboard sample (right), freezer sample (left).


The Tasting


I placed the freezer brew into two brown cups and the cupboard brew into two white cups — I didn’t tell my husband which was which until after we "cupped" the coffee. (Cupping is one of the tasting techniques used by professionals to evaluate coffee aroma and the flavor profile of a coffee.) We decided to cup brewed coffee, as we would normally drink it — though amateurishly with the equipment and experience that we have — instead of cupping samples with grounds in them.

We tasted one of each brew while still warm, and after cooled by taking the coffee into a spoon and slurping strongly to aspirate it over the entire tongue as best we could (like professional cuppers do). In tasting both specimens we went back and forth to compare the flavor profile of each to the original (fresh) batch and found:

White cups (cupboard sample):

Fragrance (beans/ground): Sharper, stronger earthy with some berry tones
Aroma (brewed): Blueberry tones, with sharper/bolder spiciness
Taste: Stronger hints of blueberry
Acidity: Some acidity, tang in flavor
Body: Light body
Aftertaste: Some earthy aftertaste with rough bitterness
Verdict: A sharper, stronger berry with spicy aroma and taste, but sharpness and bitterness added.

Brown cups (freezer sample):

Fragrance (beans/ground): More subdued, soft, fruity tones
Aroma (brewed): More mellow fruity tones
Taste: Very faint hints of blueberry sweetness
Acidity: Little to no acidity or tang in flavor
Body: Medium body
Aftertaste: Less, but some earthy aftertaste
Verdict: A retained fruity but faint aroma, mellow tone with a flat, weak, suppressed flavor.

My husband and I both agreed that between the two samples, the white-cup brew tasted better than the other and seemed to have the closer resemblance to the fresh-roasted brew (although the fresh-roasted brew tasted much, much, better).

I asked my husband to take a guess and see which was which. He guessed the white cup was the freezer specimen and the brown cup was the cupboard specimen — and was surprised to find out that it was the other way around. To be honest, even though I knew the answer, I was very surprised at the outcome as well.

We found that whatever the method, storing coffee for long periods of time, even at just six weeks, will result in a much-deteriorated taste. If need be, storing beans in the cupboard as opposed to freezing them will retain more of the fresher, original characteristics, but there is no doubt that fresh is always better. My advice: Buy no more than two weeks’ worth of coffee.

Angela Greenberg is a Christian, a veteran, military wife, a homeschooling mom of four, and a coffee lover. She roasts coffee as a hobby and loves learning about coffee. You can follow her on Twitter (@tazzadiluna).

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