Should You Be Vacuum-Sealing Coffee Beans? We Did, by Accident

Recently, Meg and I accidentally realized we were vacuum-sealing coffee beans while on a trip. It wasn’t a perfect vacuum, and it wasn’t super-intentional. But I thought it was really interesting, and maybe some fellow science-and-coffee nerds will love it too.

It also made me pose a question, that my internet poking-around didn’t definitely answer. Should you vacuum-seal coffee beans? I don’t have a definitive answer to that, but hopefully this is a fun and nerdy exploration for you. And I think I can help you think clearly about whether or not this procedure is for you.

How We Accidentally Vacu-Sealed a Coffee Bag

We Went to Coffee Fest Denver 2018

On a whim, quite a while ago, Meg and I decided to go to Coffee Fest Denver 2018. Coffee Fest seems like a pretty regular (a-few-times-a-year) industry event run by a large conference-throwing company. And it was coming to Denver, which is very near us. And we were going to be in town when it did. So we had to go!

Coffee Fest seems to be making most of its money from special training classes focused at baristas, coffee-shop owners and the like. Oh, and the whole conference is for industry-people only. Which is to say they don’t allow scrubs like us. But we’re (because of this site…) “industry people.” And they took our money and let us in the door.

Bindle Coffee is Great

We love Bindle, which is a local coffee shop and roaster in Fort Collins, Colorado (our town). The people from Bindle are nice and make great coffee. Plus, they were offering free beans at Coffee Fest.

And so, on Saturday afternoon on the way to airport, we had to stop by the Bindle booth, and take our free coffee. We were in a hurry, and so didn’t think about it a lot. But we thought to put the bag in our checked luggage for the flight to California.

Most Coffee Bags Have One-Way Valves

Now, a thing that may not be as noticed by non-nerds as it is by me is that all coffee bags have a pretty cool bit of hardware on them. Some beans I get do come in valve-less bags. But something north of 90% of the coffee bags I’ve seen in the last ten years contain some pretty cool technology: a 1-way valve. The idea is that we need to let air out of coffee, but we don’t want it getting back in. So, these are a great little solution.

The valve is the little plastic thick part you probably see on most bags. Especially if the bag is mostly plastic and a little metal. Those bags are essentially the way that you let the CO2 from the roast escape, but make sure that the bag doesn’t explode and expand in shipping.

Airplane Cargo Holds are Not Pressurized

The last piece of this puzzle is that a one-way valve, coupled with the low-pressure of an airplane cargo hold, leads to all the air around our coffee bean escaping, and not rushing back in.

So, when I pulled the coffee out at our destination, here’s what I found on June 10 (six days after roasting, twelves hours from the plane landing):

These photos aren’t perfect, but they give you a good sense of quite how good a seal the beans had fresh off the plane. Out of curiosity, I let the beans sit a few days.

But Should I Vacuum Seal My Coffee?

In my internet researching of this question of vacuum-sealing coffee beans, one of the problems that people cite is that roasted coffee beans off-gas. That’s exactly what I found when I let these sit, largely untouched. Here are my pictures from the 13th, three days after the photos above:

You’ll notice that I flattened out the base of the base for photographing here. But both to my memory and to the photos, there’s a noticeable loss in tightness of the vacuum around the beans in the bag.

This makes sense. We know that fresh-roasted beans off-gas. That’s why we often will make time for a “bloom” when brewing relatively newly-roasted coffee. This is, essentially, trapped carbon dioxide made inside of the beans which is concentrated into pockets by roasting. This slowly escapes as beans sit around, even when they’re put into a vacuum. (The gas, when freed from its confines in the bean, gets bigger.)

Why you Might Want to Try Vacuum-sealing Coffee Beans

The logic on why you’d go ahead and try to vacuum pack coffee is pretty simple: it takes up less space, and is less exposed to air. These are both benefits, but for different (and differently-important reasons). Let’s examine each:

Vacuum-Packed Coffee Takes Up Less Space

This one is kind of obvious, and pretty minor. If you make your coffee beans have less air between them, they’ll have less air between them. Air takes up space (same as everything else 🤓) and so you can take less space with less air.

I admit, this benefit pretty small and silly. Most of the space my coffee takes up isn’t spent on the air between beans. It’s the excess packing material that surrounds that air-and-bean combination. And most ways I can think of vaccum-sealing your coffee, you’ll still have some excess packing material. So your benefit may be more than zero, but not by a lot.

Vacuum-Sealed Coffee Should Be Fresher

This one is what I was hoping my research would find a definitive article on, and it definitely didn’t. Turns out, our article on vacuum-sealing coffee beans might be the best the internet’s got right now! I think it’s reasonable to assume that oxidation is bad for roasted coffee. (It’s oxygen, that thing that keeps us alive, that makes most food spoil.) I found an article saying as much about coffee freshness.

If, indeed, oxygen is bad for coffee, then decreasing the amount of oxygen (and air, which is typically ~17% oxygen) around the beans would make them last better. Decreasing the amount of oxygen in contact is the same reason that I’ve seen people use wine preserving gas on coffee, wine, and liquors.

(Very random aside: those bottles are comically light. I think because they want them to be at relatively low pressure for shipping safety. So they’re very unlike an oxygen tank, and they’re just gas inside.)

It follow that if you don’t want to use an inert gas on your coffee (which would be a viable alternative) you should vacuum-seal it if you can. Vacuum sealed coffee would have less oxygen around it, it’d thus oxidize slower (or not at all) and then taste good for longer.

How Would You Vacuum-Pack Coffee?

I’ve never vacuum packed anything with a machine. Not once. But I get how it works, and have done it before with my lung. When you do that, you get a plastic zip-lock bag and a straw. You mostly seal the back but for the straw hole, you suck out all the air you can with the straw, pull out the straw, and seal the bag as soon as you can after that.

If I decided to take seriously the idea of vacuum-preserving my coffee, I’d probably buy a FoodSaver. They seem to be the consumer-vacuum-packer brand that has succeeded. You can buy supplies for them anywhere from Amazon to Walmart. I’d just take my coffee, divide it into reasonably sized portions, and seal little bits at once. For me, that’d be something like at 32g batch for a Kalita Wave pour over.

When I wanted to use the coffee, I’d de-vacuum it. Grind it. Brew it. Drink it.

Downsides of Vacuum-Sealing Coffee

  • Off-gassing (which we discussed above) is likely to make your nice tightly-vacuumed portions slowly expand. Especially if you do it when your beans are relatively fresh.
  • It’d be time-consuming to make all those vacuum-packs. As I mentioned, I’ve never really used a vacuum machine. But even the quickest I’ve observed take almost a minute of cutting, preparing, and sealing the thing you’re using it on.
  • You’re going to use lots of excess plastic around your beans. I feel like conventionally packed coffee, like the Bindle above, is fine on waste. It’s not great, but I’m not embarrassed. Packing 2-4oz packages on your own after getting those would be wasteful. Uncontestably so.

Vacuum-Packed Coffee is Cool, but Buying What You Use is WAY Easier

In general, I thought it was fun and interesting to accidentally vacuum seal coffee. If I magically came into possession of both a vacuum-sealer and a whole bunch (1kg/2lbs or so) of great coffee for home use, I’d probably try it in earnest.

But for me, the solution to this whole question of vacuum-sealing coffee beans is easier than that. Buy just the coffee you expect to use in the next few weeks. Use your coffee at the same rate you’re buying it. And you’re set. No need to worry about going to exceptional lengths to preserve it. That’s the option I’d favor, every time.

12 Replies to “Should You Be Vacuum-Sealing Coffee Beans? We Did, by Accident”

  1. We buy ours in bags from Sam’s club. Natural no additional flavors or ingredients and in bean form but when we get home we put it in Mason jars and seal it to retain the fresh smell and oils. Its definitely different and smells different as well.

  2. I use widemouth mason jars and the Foodsaver jar sealer attachment to store my coffee beans. It lets me store my vacuum sealed beans in jars which are about the same size as my grinder’s hopper. So far so good. I’d feel too guilty using all the plastic the bags would require… If you already have a Foodsaver it’s just a few dollars more for the attachment – I find the wide-mouth one works 100% of the time, where as I struggle with the regular sized one.

    1. Use two flat canning lids instead of one when using regular size lids The top one usually falls off when taking the foodsaver attachment off

  3. As someone who owned a set of tools for sous vide, I would say vacuum beans into small single serving bags aren’t much of an effort personally. It is extremely quick and easy plus you can always reuse those bags, esp those designed to be reused, for the same beans at least (or just wash the bags and turn them inside out for drying)

  4. Hi there,
    Passenger airline cargo holds and cabins are pressurized just the same. Equivalent to the atmospheric pressure at 8000 feet. With the exception to the Boeing 787 with is pressurized to around 6000 feet. The whole plane is a cylinder to resist the pressure difference outside the plane. If the cargo hold below your feet wasn’t, the floor would bend as the pressure difference on that flat surface would be eminence. Plus, live animals travel in the cargo hold too. They can’t survive at the atmospheric pressure of 35,000 feet. Hiking to high altitude with sealed containers will yield the same result.

    I use mason Jars where applicable for vacuum sealing.

  5. I use a large FoodSaver container that fits a 2.2 LB bag of beans. I keep just a small amount of beans in the grinder hopper to minimize air exposure and reseal the container. Takes no effort, considering the sealer is always on the counter. With daily espresso and morning cappuccinos, I refill the hopper about every other day.

  6. We buy a lot of the Dunkin Donuts coffee from where the shops where they sell coffee. The grocery store DD coffee is not the same as what they sell at DD stations.
    At Christmas time they sell their coffee for as low as 4 bags for $20. These bags are all one pound bags.(16 oz) and we stock up during this time, so I will suck the air out with my foodsaver machine. I like the foodsaver because the heat strip is wider for a stronger seal.

  7. I would question pulling a vacuum on coffee beans. You would be better off, it seems to me, to place the beans under an inert gas with a moderate pressure above atmospheric pressure.
    The vacuum encourages a speedier gas flow out of the beans.

  8. Hi David & Meg, thanks for your article on a very intriguing question.

    Possibly of interest to you:

    Way back in the ‘90’s I got a year’s free subscription to the USA magazine Camera & Darkroom for suggesting a way to extend the life of photographic chemicals; and I have, over the intervening period, used it for many other applications – coffee beans included.

    Very simple: use any bottle, big or small as needed, with an appropriately sized neck and utilize the Vacu Vin ( wine preserver ) rubber stopper and associated separate manual vacuum pump.

    Thus one can have a number of stoppers and 1 pump. Just google Vacu Vin Wine Preserver and there is a lot of info on it. ( It achieves about an 85-90% vacuum ).

    Using the bottles is appealing as it’s glass and reusable. And quick and easy to re-apply a vacuum after pouring out beans dosage. Also, I have put these in both fridge and freezer.

    Thus a good starting point for anybody who wants to do some comparative experiments.

    All the best
    Derek McKenzie

    South Africa

  9. I am now finding good reason not to vacuum seal coffee! The “Off Gassing” of Co2 that the bean produces provides a protective barrier against oxygen, the oxygen that will eventually make coffee bean stale. In vacuum sealing the coffee this Co2 gets pulled from the bean prematurely, when the oxygen is let back in on an everyday basis to remove coffee beans for brewing and grinding, the Co2 is replaced with oxygen, causing premature aging of the bean… Just something to ponder!

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