It’s All in the Grind

In this week’s blog post, Barista trainer Tom talks you through the tricky issue of grind and gives you some tips on how to use it to improve your home brewing experiences.

WHAT IS GRIND?

When we talk about grind we are referring to the size of the coffee particles we are using for our brewing. Using the appropriate grind is one of the best ways of ensuring that we brew delicious coffee and being able to control it is probably the most useful tool in our brewing arsenal. With this in mind, my first piece of advice to any home brewer is always to get hold of an adjustable burr grinder!* These don’t have to be expensive – simple manual versions can be found for as little as £30 and links to some good domestic options appear at the end of the article.

This is how you make pesto, not coffee
This is how you make pesto, not coffee

WHY IS GRIND IMPORTANT?

The size of the grinds that we brew with has a huge impact on the rate at which our coffee brews because it determines the total surface area of coffee that is exposed to our brewing water. The finer our grinds the larger the surface area and therefore the faster the soluble compounds will be dissolved. A helpful analogy is the way in which a spoonful of sugar dissolves into a hot cup of tea relative to the equivalent dose of sugar in the form of a sugar cube.

We use coarse ground coffee in a brewing method such as a cafetiere, which has a relatively long brew time (4 minutes or more) precisely because we want a relatively slow rate of brewing. This grind however would make for a weak, sour and under-brewed espresso as the brew time would be much too short to extract everything we wanted from the coffee. If, however, we used fine espresso style grinds for our cafetiere the opposite would occur and we would over-brew our coffee in a 4 minute steep.

WHICH IS THE “RIGHT” GRIND?

Grind size should be directly related to the contact time between water and coffee in our chosen brewing method. Generally speaking the shorter the brew time, the finer the grind should be. Here is a quick run-down of grind sizes and brewing methods from finest to coarsest with some rough size descriptors:

BREW METHOD DESCRIPTION
Turkish (Ibrik) * talcum powder
Espresso (commercial) powder/slight grittiness
Espresso (domestic) a little finer than table salt
Aeropress (traditional method) table salt
Moka Pot table salt
Aeropress (inverted method castor sugar
Filter (V60, Kalitta) castor sugar
Siphon castor sugar
Chemex granulated sugar
Cafetiere Sand

*Turkish coffee is really weird and actually has a long and unusual brewing method that flies in the face of received brewing wisdom. For this reason it is the obvious exception to our finer grind = shorter brew time rule!

Please note that these are only starting points – you will always get best results from following a brewing method and tasting the results. Sour/thin coffee indicates that your grind may be too coarse. Dry/papery/bitter coffee indicates that your grind may be too fine.

PRE-GROUND COFFEE

If you don’t have access to a grinder then you don’t have a great deal of control over your brewing. Furthermore, the available choice of grind sizes may be very limited. Supermarkets tend to offer just one grind size that may or may not be appropriate to the coffee brewing method you are using. Every supermarket is different and it really is pot luck as to what you are going to get when you open the bag. I really like some Aldi coffees but they come up rather fine for my filter brewer and this makes it hard to achieve the desirable 3 minute brew time for my Kalitta dripper and tends to over-brew in a cafetiere.

3 TIPS FOR GETTING THE BEST FROM PRE-GROUND COFFEE

  • Change your brew time – With a cafteiere or aeropress it is easy to change your steep time so just shorten it if you feel that your pre-ground coffee is too fine for the recipe you are using. It’s not so straightforward to vary steep time with other brewing methods such as espresso or filter so if these are your methods of choice you would really benefit from biting the bullet and getting a grinder
  • Change your brew method – If you are stuck with pre-ground coffee and not that fussy about the way you make it, just plump for a brew method that suits your grind rather than struggling with coffee that is too coarse or fine
  • Change your coffee – Supermarkets and commercial coffee suppliers often do a pretty bad job of communicating grind to customers. Their packs of coffee often say “suitable for all coffee makers” when we now know that this is not exactly true. Furthermore, this “omni-grind” is very different from one manufacturer to another – Aldi’s for example comes up very fine compared to others. Sometimes just switching up your coffee brand can leave you with a more appropriate grind so explore the range in your supermarket or local store

RECOMMENDED GRINDERS

Manual Grinders <£50 = Rhino, Hario, Porlex >£50 = Orphan, Knock, HG One

Electric Grinders <£50 = Don’t go there!  >£100 Baratza, Mahlkonig, Macap, Rancillio