30 Aug 2014

Why do we: Use Different Grind Sizes for Coffee?

In my blog on why we measure everything when brewing coffee, I talk briefly about using different grind sizes. And in my tutorials you can find different grind size advices for different brewing methods. 

Why do we use different grind sizes for different methods? The answer, as most times, is based on the principle of extraction. Brewing coffee is all about extracting flavours from ground coffee. Coffee consists of different flavours and aromas that all extract at different times in your total extraction time. Some are more volatile and are extracted at the beginning of your brew. Others only appear a little later. The least pleasant flavours of the coffee, such as bitters, will be extracted from the beans later in the brewing period. You want to make sure you extract the flavours you want, and leaving those in you do not want.

So how do you influence the extraction of your ground coffee? There are a lot of things that influence this, the bean, your water, and so on. But the basics are; first your ground coffee to water ratio. Then also your total extraction time, in other words, how long your water is in contact with your ground coffee. And lastly, your grind size.

The finer your coffee grind, the easier it will be for the water to extract flavour, and so, the shorter the water has to be in contact with the coffee. The coarser your coffee grind, the more time the water will need to penetrate your grounds and the longer your extraction, or contact time, should be.

So what grounds are used for what methods? The methods that use a long contact time, and where the coffee is submerged in the water, need the coarser grinds. The medium grinds are usually used for drip coffee. With these methods the water usually runs through the ground coffee, instead of submerging. The finer grinds are for methods that use a shorter contact time, or even brew coffee under pressure, such as percolators, espresso pots and espresso machines.

The aeropress is a bit of an exception. There is no right grind for the aeropress, and that is because it is so versatile. You can create a recipe with a short contact or long contact time. You can submerge the coffee grounds in water, or let the water run through. You can use the guidelines below and create the recipe you love.

Overview of grinds

Turkish grind
Turkish grind looks like fine flour and is very powdery. 
This method is an exception on the rule. For such a fine grind the extraction time is a lot longer than expected. This is why this brew is often quite bitter and thus often mixed with sugar. Want to make Turkish coffee? Check out one of the recipes here.

Super fine grind
Super fine grind is used for espresso and is a little coarser than powdered sugar or flour, but it is very similar. But if you run your fingers through, you still feel some grit, which you will not feel at all in a Turkish grind.
Extraction time: 17-40 seconds

Fine grind
Fine grind is used for espresso pots, percolators and some cone shaped drip filters. Fine grinds look like sugar or salt. Especially when you run it through your fingers.
Extraction time: 1-4 minutes

Medium grind
Medium grind is used for drip coffee, both cone shaped as flat bottomed. It is also used for vacuum pots or syphons. It sits between salt and coarse sand.
Extraction time: 2,30-4 minutes

Medium to coarse grind
Medium to coarse grind is used for the Cafe Solo and the Chemex. The grind sits between coarse sand and coarse sea salt.
Extraction time: 3-4 minutes.

Coarse grind
Coarse grind is used for french press and often for coffee cuppings. However, sometimes cuppings use a little finer grind. The grind is like coarse sea salt. 
Contact time: 4-6 minutes

Very coarse grind
Very coarse grind is used for cold brews.
Contact time: usually from 8 hours to 72 hours

1 comment:

  1. Tof Cerianne, precies wat ik zocht = exactly what I was looking for.


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