On the commercial coffee LinkedIn group, there was a question on vacuum packing freshly roasted coffee to keep it fresh. When I was at roasting school, we learned how freshly roasted coffee gives off CO2. This is why you need a can or bag with a gas relief valve. Recently, I decided to get a hand vacuum bagging system. It is a low-cost unit available in Canada from Home Hardware for only $20. For a small cost I could experiment with vacuum packing coffee. The bags are reusable but not cheap, at about $1.25 each. As I just want to use the bags for my coffee at home, the price per bag is not a factor. If the coffee was for resale, a much lower cost per bag would be needed.
The Vac N Store kit comes with three bag sizes. My sample roaster does 1/2-pound roasts that fit nicely in the small bag. By sealing the bags, the coffee is not exposed to oxygen, which is what contributes to making coffee stale. What surprised me was how much gas is released by the beans. Here is a bag of just-sealed, freshly roasted coffee. The little hand pump does a fair job of removing air, but is not commercial grade.
Here is the bag 5 days later.
I was surprised how much air was in the bag. This is not from leaking. Here is a large bag of decaf green coffee beans that I packed several weeks ago. The vacuum seal is still tight.
I put the bagged roasted coffee in my grinder this morning, and it was very nice. Did it hold the freshness better? I am not sure. I need to do a side-by-side on the same coffee, one roasted a week ago and stored, the other roasted the day before.
My question coming out of this is how do companies like Illy vacuum pack coffee? I believe theirs stays tightly packed because the coffee is ground. Perhaps on the next roasting batch, I will bag 1/2 as beans and in a second bag, 1/2 ground and see how it compares.