Coffee bean storage: the latest research on the dos and don’ts

Coffee bean storage: the latest research on the dos and don’ts
28/01/2017 Kirsty
coffee beans in tin

Protecting your beloved coffee beans from their enemies and making a more flavourful cup of coffee might just have gotten a lot simpler – and cooler!

It’s been a long-time controversial debate on the coffee scene – whether or not to freeze your beans. Scientists from the University of Bath in England have published research that not only adds value to the argument for cold storage, but offers a new approach to extracting a more flavourful cup: the cool grind.

Coffee has four arch-enemies when it comes to flavour: air, moisture, light and heat. Our storage methods usually involve minimising our coffee’s exposure to them:

  • Using airtight containers because air degrades the oil, known as caffeol, that gives coffee that exquisite flavour and aroma.
  • Storing coffee in dry places because coffee beans absorb moisture and the odors and tastes around them. Moisture will also speed up that degradation process.
  • Keeping beans in the dark, in ceramic or opaque glass canisters, because light speeds up the oxidation process.
  • Keeping beans away from heat sources, like direct sunlight and stove tops, because heat also accelerates the deterioration of flavour.

Like a lot of things, when it comes to coffee: the fresher, the better…freshly roasted…freshly ground. So between the roasting and the grinding we want to do our bit to protect our beans and keep them as fresh as possible.

“ better beans, better stored, better coffee”

The traditional belief behind storing coffee beans in the freezer is that it prolongs that sought-after freshness, which is especially useful if you’re buying larger quantities to last you for more than a week. But there are also questions about whether the freezing process impacts negatively on the beans and their flavour. Specifically, whether the moisture in freezers dilutes the flavour oils, and whether odours taint them.

From their research, the U.K. scientists are proposing that chilled beans can give you a better grind and, consequently, a more flavourful cup of coffee. How’s that? Well, they ground beans at different temperatures – from room temperature to as low as -196 degrees celsius- and found that, on a sliding scale, the colder the bean when ground, the finer and more uniform the result.

So what? Well, this is important because flavour extraction in coffee brewing is, in part, related to the amount of surface area of the grounds exposed to water. So, the finer the grind, the more quickly the flavour can be extracted. Also, the more uniform the ground particles are, the better and more consistent the extraction of flavour compounds. This means that the coffee needs less time to be brewed, or that you could get more coffee from the same amount of beans. It also means there are potentially less beans being discarded without being fully extracted.

This is good news all round. More efficient extraction is more cost-effective for businesses, and that’s good news, ultimately, for the buyer’s wallet. It’s also good news for roasters producing coffee blends as they will potentially be able to get similar extraction rates for different beans. This would lessen the chance of off tastes due to variance in particle sizes. In the bigger picture, it’s good news, too, if the reports are true about coffee production being in decline due to climate change (but that’s another story on its own!)

But despite this development in storage, coffee’s enemies are still at the gate and can’t be ignored. The main threat with cold storage is moisture. So, utmost care still needs to be taken to minimise your beans’ exposure to it. Here are some things to consider:

  • The more airtight your coffee canister, the better.
  • A deep freeze is opened less than a fridge-freezer so there is less potential exposure to the enemy.
  • When taking beans from the freezer, take what you need for your brew and return the rest as quickly as possible to lessen the chances of condensation (moisture) forming on the frozen coffee.
  • Spare a thought for your grinder, too. Grinding frozen beans brings moisture which, in turn, can bring rust. So, clean and dry your grinder after each grind.

We love it when science offers simple solutions in our lives. But when it offers a cooler way to improve the coffee tasting experience, too, that’s something else! So, go make some room in your freezer for a cooler more flavourful grind – just make sure you keep the moisture wolf from the door.