As a speciality coffee roaster, we are often asked questions regarding freshness and roast dates - what it means for us, and what it means for the consumer. In this blog, we’ll dive into the question of what is freshness in coffee through all stages of the coffee-producing process, from origin, to roastery, to your kitchen table.

If you want a TL;DR, scroll to the bottom of the page. But first, a little background as to what coffee beans actually are, and how they are transported across the world to our roastery in Surrey.

From Picking to Packing

The coffee beans we buy are the seeds of coffea arabica plants. Depending on the varietal, coffee plants can grow up to well over head height and yield in the hundreds of kilograms per hectare.

Each single coffee cherry contains two seeds, and these are what we call coffee beans: These beans are extracted from the cherry using a range of techniques, the most popular being washed and natural processed.

Once they have been sorted for size and had defects removed, they are dried until they reach the required moisture content, then put in the coffee sacks that are so familiar to coffee lovers around the world.

Depending on availability of shipping and logistics services, it may take several months for this green coffee (as it is known) to reach our roastery. In order to help slow the drying process, a plastic bag known as a GrainPro is usually used inside the traditional hessian sack. These GrainPros are very helpful to us, as they contribute to being able to purchase a whole year’s worth of coffee upfront from a producer and ship it all at once.

Green coffee beans are a living part of the plant kingdom, and remain so right until they enter our roaster. When stored correctly in GrainPros and sacks, green coffee will last at least a year before it dries out too much and loses its flavour.

Roasting and Resting

During roasting, carbon dioxide is absorbed into coffee beans. We want much of this CO₂ to dissipate before drinking our coffee, ensuring a more rounded and mellow flavour. Our Head Roaster Elizabeth Furth says, “When there is still a lot of CO₂ trapped within the beans, a ‘barrier’ is created by the gas that can hinder water making good contact with the grounds.”

While it is not dangerous to consume coffee which is fresh out of the roaster, we naturally want our coffee to taste its best. This is one of the reasons why we don’t dispatch very freshly roasted coffee, but rather roast a week in advance - our view is that our beans need around a week minimum to degas - in fact, beyond cupping for quality control we don’t formally taste or serve any coffee that is less than a week old. Elizabeth explains, “Freshly roasted coffee naturally degases after the roasting process has been completed. Depending on the brewing method used, the degree of degassing is something that should be taken into account.”

What is the optimum freshness for coffee?

This is the million-dollar question, and as ever, the answer is 'it depends'.

“Espresso brewing is definitely different from filter brewing when it comes to 'optimum' freshness.

For espresso, I believe the optimum window is one to three weeks off the roast - although this does depend on the roast level. A lighter roast, particularly those which are Scandinavian-style, will stay fresher for longer.

For these lighter filter coffee roasts, I enjoy them any time from one week up to three months after roasting - but it's still important to keep the beans in an airtight bag or container! The 'barrier' between the water and the grounds breaks down over time, and this should actually enhance the flavour up to a point when brewed with something like a V60, cafetière, or with my personal favourite, the AeroPress. You may need to agitate (stir) the coffee in the water a little more as the coffee ages.

Up to three months is much longer than some would say you could leave roasted speciality coffee, but it is actually fascinating to observe how the flavour profile of filter coffees change a little as they degas and mellow out. Of course to keep the coffee in good enough condition that you can experiment like this, you'll want to store it in a good bag with a valve that lets CO₂ out but doesn't let oxygen in - and you will need a grinder so that you can grind on demand and only take what you need.”

Does this mean I should throw away old coffee?

Not necessarily. Old coffee isn't harmful, and if it's stored in an appropriate bag with a one-way valve it will be several months before it really begins to lose its flavour.

In general, the longer the extraction the better older coffee will cope. For example, a cafetière is a great way to use up slightly older coffee as the grounds have plenty of time to soak and extract slowly.

If we take this to its logical end game, we get to cold brew. Making a cold brew coffee requires using cold water and soaking the beans for a very long time - up to 24 hours! Brewing this way will help you achieve maximum flavour from old coffee beans.

A quick reference guide to optimum coffee drinking times

Here are the times where the flavour of our coffee will be at its best, where day 0 is the day of roasting:

• ESPRESSO/STOVETOP | 7-21 days for optimum flavour (still very good to drink up to 90 days)*
• FILTER/DRIP/AEROPRESS | 7-90 days*
• CAFETIÈRE/COLD BREW | 7-90 days*

Be sure to store your coffee in its original bag or in an airtight container to maximise the flavour of your coffee over time, and always buy whole beans if you can. If you have a grinder, as your coffee ages you may wish to use a slightly finer grind setting and/or agitate it more thoroughly to ensure optimum extraction.

*Our coffee will not go mouldy or be otherwise unsafe to drink after 90 days - this is just when we think it's at its best!