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Manipulating Your Brewed Coffee: Grind Size
This article is the second in a series of four articles about manipulating the strength and flavor of coffee. The series cover the four major techniques for altering a coffee brew: Ratio, Grind, Time and Temperature.

The Tricky Variable

Grind size is one of the hardest things to explain and think about in terms of brewing coffee. The reason is two-fold: 1. When you grind coffee, the particles are never just one size. 2. There isn’t a way to quantify grind because ground coffee particles are too small to count or measure without sophisticated equipment.

Different models of grinders don’t grind alike; even different units of the same model can be calibrated differently. So while we can use phrases like “fine grind” or “medium grind” there is not very much we can do to standardize grind size in a numerical system.

Visualizing Grind

Because we can’t communicate grind size using numbers, we have to use visual clues to find the right starting point, and then do brewing trials to dial in the ideal grind. Here are some basic visual comparisons:

Very Fine (Espresso) == Superfine Sugar
Fine == Table Salt
Medium == Coarse Sand
Coarse == Kosher Salt

Using Grind to Change Your Brew

The chart below shows the results of six brews I did with the Malawi Msese, which is one of the coffees currently in our single origin subscription pack. Each of the brews uses a grind size between 8 and 10.5 on the EK43 grinder. The grinder goes from 1-11, so our experiment used about 25% of the total grinder range. Aside from changing grind, I used the same parameters for each brew: Chemex, 1:15 Ratio, 20g coffee, 300g water, 3 min 45 sec brew time, 205 F water.  

The chart shows Grind graphed against TDS, which is Total Dissolved Solids. TDS measures brew strength. According to the SCAA, the ideal range for TDS of brewed coffee is 1.2-1.4%. The chart also indicates how flavors changed along with the intensity of the brew.

Using the parameters in this experiment, there was a perfect direct relationship between grind and TDS.  For each half step on the grinder, the TDS measurement went down by two one hundredths of a percent (1.43% TDS to 1.41% TDS.) When I chose the parameters for this experiment, I expected to see a results range from approx. 1.5%-1.2%; I was surprised the range was so small. Even though the TDS range was relatively small, there were still very dynamic changes in the coffee’s flavor and the intensity change itself was noticeable. 

This Malawi coffee was very easy-drinking, while also showing a complex range of flavors. Starting in the middle, with the brew that used a “9” grind, I got flavors of pipe tobacco, currant, lime rind. This was my favorite brew with a TDS of 1.39%.  Pipe tobacco, which is sweet, earthy and complex is one of my favorite tasting notes. Going to the “8.5” grind, the tobacco flavor is intensified and a deeper black cherry note replaces the currant and lime. At an “8” grind the tobacco note becomes more raw, the cherry intensifies and a blackstrap molasses note comes into play. Going the other direction, the “9.5” grind coffee loses the tobacco note altogether and replaces it with chamomile, which is more delicate, but shares a similar hay-like quality and rustic sweetness. The fruit notes become more prominent and sweeter. At “10” this coffee tastes like cherry limeade—bright and sweet with a light mouthfeel—so different from the intense earthy flavors we experienced with the finer grinds, but still delicious. At “10.5” it continues to get sweeter and less tart, like a key lime pie.

The Best Home Grinder

Brewing coffee well isn’t about having the most expensive equipment, it is about understanding the principles of brewing and executing them with the equipment you have available. This is why it is possible to brew coffee without a grinder at all. That being said, we’d be remiss if we didn’t recommend the Baratza Encore grinder to anyone interested in upping their home coffee game. A good grinder will do wonders in allowing you to dial in your brew and will allow you to taste the wonderful range of complex flavors discussed in this entry.

Keep an eye out for the next entry in this series: Brew Time!

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