Coffee Bean Storage - Vacuvin?

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dbartramr
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Joined: 17 years ago

#1: Post by dbartramr »

Recently I started storing whole beans bound for espresso in an acrylic storage container with a rubber valve and pump, such that it's possible to suck most of the air out. The valves were first marketed for keeping wine by removing the air from an opened bottle of wine, and the containers are also available for food storage and marinading (the Vacuvin brand being the most common).

However, it seems as if keeping the coffee in a near-vacuum environment may be affecting the beans' properties. Namely, the beans seem to require a much finer grind, and they don't pack well from tamping. I haven't experimented thoroughly to verify that the vacuum storage is the parameter that's causing this, but has anyone else had experience with storing beans in a vacuum, rather than just an airtight container at "room pressure"? Has anyone studied the effects of vacuum storage on beans?

One theory is that storage in a vacuum sucks gasses and moisture-laden air out of the bean, and once reopened, replaces those gasses and air with normal, every day, pedestrian air, which eventually changes the characteristics of the coffee once ground and tamped.

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HB
Admin
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#2: Post by HB »

The difference you see in pour times may be the humidity (our house is now around 30% relative humidity). A number of members mentioned vacuum sealing in Refrigerator or Freezer for Coffee Storage?, especially for freezer storage. How long are you storing for and are you dipping into the container, or once it's open it's open?
Dan Kehn

CoffeeBeau
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Joined: 18 years ago

#3: Post by CoffeeBeau »

I just picked up a vacuum vin coffee storage device my self. It looks good on my counter top, and seems to help with the bean freshness. But I dont know if that is an issue. I home roast, and my beans are gone in a week or less.

Bob

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iginfect
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#4: Post by iginfect »

Bob, I think the discussion is on green beans, not roasted.

Marvin

dbartramr (original poster)
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Joined: 17 years ago

#5: Post by dbartramr (original poster) »

I noticed a difference after sealing the (roasted) beans overnight, and I generally seal them back up after I've pulled my shots.

Humidity certainly could be the central issue. When I open the bag of espresso, the humidity in the bean would be equal to whatever was in the bag; once transferred to the vacuum container, sealed, and vacuumed, I suppose the beans would then quickly take on the humidity of the air in my room once reopened, and would stay the same thereafter. In this particular case, I had kept the beans in their bag for a few days, dialed in my grinder, and then put them in the new vacuum container, after which the grinder seemed to be way off.

So, the conclusion may be that the lined paper bags that beans come in seal, but also maintain some humidity, much like any plastic bag would; vacuum containers may prolong bean freshness, but also change moisture content in the beans more quickly, for which grinder adjustments may be necessary. Anecdotally.

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timo888
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#6: Post by timo888 »

I wonder if micro-pockets of gas in the roasted bean are sucked out by the vacuum and then the cavities fill with oils?

Regards
Timo