Freezing

Introduction¶

Freezing coffee is a great way to take control of your coffee inventory in a variety of ways. It allows you to essentially "stop the clock" on the ageing process once the coffee is sufficiently rested. What you do with this invaluable tool if up to you, and is limited only by your imagination.

Once coffee is in the freezer, you have much longer to enjoy it because all the chemical processes within the beans are massively slowed down. Exactly how much time freezing adds to shelf-life is up for debate, but the Arrhenius equation suggests this to be about 5 years or more.

I started freezing coffee in 2018 and used it to create Manchester Coffee Archive, a local resource for hosting themed coffee tastings, but you don't have to do that: use your freezer to keep a healthy stock of coffees at their optimal resting time and never run out of coffee again!

What follows below is a summary of key information in relation to freezing: a deeper dive into the world of freezing can be found on the MCA website "What We Know About Freezing Coffee", which includes some potentially useful workflow suggestions and background information.

Equipment Required¶

You will need:

Freezer - set aside a space in your freezer, this could be plastic tub, a whole drawer, or an entire freezer. It is very tempting to hoard coffee once you get into freezing, so my advice is to try and stick to your designated storage area, if possible, at least until you get your dedicated coffee freezer(s).

Optional:

Tape - duct tape or electrical tape is great for sealing up valves on bags, if present.
Containers - if you aren't bagging up entire bags you'll need some containers: reuse anything you can find with a tightly fitting lid, or purchase some containers in a size that suits your needs.
Vacuum sealer and vacuum sealing plastic - vac-pack yourself some nice, neat little bags.
Masking tape and marker pen - use this to label your coffees however you see fit.
Label printer - if you want to make things super organised.
Wireless thermometer - allows you to keep an eye on your precious beans (I like to ensure my freezer is running at -20°C).
Rubberised gloves - handy for retrieving cold containers of coffee from the freezer, especially with glass bottles.

Reusable Containers¶

Any container that is made of non-porous material and sealable can be used for storing coffee in the freezer. You will want to avoid exposing the coffee to the damp freezer air as much as possible so your coffee doesn't smell of (potentially) fishy freezer air. The capacity of a container will depend on roast level, density and the coffee variety.

Some examples:

The original bag - press out the air, tape up the bag and you are good to go. Note that unlined paper bags are porous, so in this scenario double-bagging in a zip-lock bag is a good solution. As a precaution, I put any taped-up bags inside a zip-lock bag for my own peace of mind.
Centrifuge tubes - usually 50ml in size, with a 20-22g approx. capacity
Specimen containers - available in a range of sizes:
40ml - 16-20g approx.
60ml - 25-29g approx.
90ml - 33-41g approx.

The best place to find centrifuge tubes and specimen containers is generally eBay, AliExpress and laboratory supply companies.

Vacuum Sealing¶

A very popular tool for neatly packing up coffee in preparation for freezing, and a great way to maximise your storage space. If nothing else, tapping a vac-pack of coffee with your finger is one of life's great pleasures.

Vacuum sealers: these will pull a ~80% vacuum for the air that remains inside the flattened vac-pack, which means there is still some oxygen in there, but don't worry about that because this coffee is going into the freezer where the oxygen will have much less of an effect. Note that specialised embossed/textured bags are needed for this kind of vacuum sealer: these will often be supplied with the sealer. Making your own bags with a roll of vacuum-sealing plastic can be a good way of customising your storage and cutting costs: 12cm or 15cm width is a good start, but note that you generally need original edge on each side of the pouch to ensure a complete seal is made.

Chamber Sealers: these are the beefy, commercial-style vacuum sealers which can pull a 99% vacuum for the air that remains; however, they are big, expensive and noisy. One benefit though is that any kind of heat-sealable plastic can be used with these hefty units.

FAQs¶

Does coffee actually freeze?

Nope, it just gets really cold - there isn't enough water content for it to actually freeze.

Do I need to defrost the coffee before I use it?

Nope - dump those beans straight in the grinder and enjoy. In my opinion, the only time where it is useful to allow beans to come to room temperature is when you are re-packaging them: in this scenario, I generally let the beans come to room temperature and then wipe any condensation off the container before portioning out the beans. Note that condensation forms when cool air comes into contact with warmer, non-porous surfaces.

What is better: vacuum seal or reusable container?

Not sure! I developed an experiment to test this but have never completed. However, I routinely use coffees that have been frozen in their original taped up bags for over a year and the results have been tasty - so, take from that what you will.

Can you re-freeze coffee?

Yes, in the words of eminent coffee freezing icon Michael Cameron: “this ain’t chicken, you can re-freeze”.

What about green coffee?

Yup, that works too - George Howell, Colonna and other roasters around the world are into this.

How do I keep track of all this coffee in my freezer?

I like to use spreadsheet, but you could use a whiteboard, a notepad, or use a helpful app such a Bean Conqueror, which has a built in "frozen" option for monitoring your coffee inventory.

I have another question, help me!

Feel free to reach out to me (Tom) at Manchester Coffee Archive if you have any other questions about freezing coffee. I can also be found on the Mystery Coffee League Discord (@teaeff).