Green coffee (unroasted coffee) storage for home roasters
This is my recommendation for green coffee storage, you may have heard or read something different, but this is what I believe works. For commercial roasters the challenges are a little different and each will have their preferred methods to prevent the various environmental "attacks" on the coffee. I won't be covering any commercial storage issues here, although some of the principles still hold true.
How does your green coffee like to be stored
- It likes the same sort of humidity you do
- It like similar temperatures to you, a cool room is ideal (the sort of temperature most people like a bedroom to be)
- It likes to breathe a bit (again like you)
- It's not dead keen to be left in the sun all day (again a bit like you)
What doesn't it like
- Strong smells and cooking odours
- Damp conditions
- Airtight conditions, when it can't breath
- Freezing (very damaging to green coffee)
Working on those very basic principles above, the best place for storage is not usually outside, unless you have a properly damp-proofed building, with heating if necessary and enough insulation to protect from freezing or very cold temperatures. You would also have to consider vermin and ensure the building is sealed from entry by vermin and properly trapped and baited to deal with any intruders who might get in.
In the house find the coolest room you can and store the coffee there, of course not next to a radiator and not near smells of cooking food. What you store the coffee in is also very important! I read advice to keep green coffee sealed in plastic bags or containers, this is not a good idea and coffee does not appreciate being stored like this.
As soon as your green coffee arrives (I’m thinking of the 27kg of 9 different coffees in the 1st greens club delivery here), you need to get it out of those plastic bags and into some suitable storage. I will be mentioning Tesco here not because their products are any better than anyone else’s, it's just where I got mine and the ones referred to in the photographs (all prices correct at the time the article was written). Suitable storage is actually value pillowcases (50/50 polycotton), they hold a decent amount of coffee and as you will no doubt be finding out 27Kg is a very "decent" amount of coffee (more perhaps than it sounded). I bought 9, now for a very good reason I didn't wash them. My understanding that the fabric treatments that protect them in storage are unlikely to harm the coffee, but could be beneficial in preventing certain types of spoilage (I’m guessing here, but if you want to wash them…fine).
You can use the inner wash care label and a normal black felt pen to write the name of the coffee, then simply tie a single knot in the neck of the bag and pull the label forward so it is clearly visible. That’s pretty much it. From time to time (every month), lift the bags and mix the coffee around, try and ensure they are adequately ventilated. The reason I bought blue pillowcases was simply because they didn’t have any white ones. Cost of these value pillowcases is 90p each and they should last a very long time. Perversely the cheaper ones are probably better because they are thinner and will breathe better.
A quick update
It has been pointed out to me (by Toast21) that it would be simpler to find the label if the whole pillowcase was simply turned inside out. I with embarassment have to admit that this relatively simple idea just had not occurred to me!