Manipulating Your Brewed Coffee: Brew Ratio

This article is the first in a series of four articles about manipulating the strength and flavor of coffee. The series will cover the four major techniques for altering a coffee brew: Brew Ratio, Grind, Time and Temperature. A more condensed version of these posts can be read in our Brew Guide.

The Heart of Brewing

Brew Ratio refers to the ratio, by weight, between water and coffee and it is the heart of the brewing process. Even if you don’t use a scale or a scoop to measure your coffee, each brew has a ratio that is one of the primary influences on the final strength and flavor of the cup.  


When we write or talk about ratio at Good Folks, we always express it in these terms:

Weight of Coffee : Weight of Water

A good ratio to start with is 1:15. 1:12 is a very tight ratio and it yields an intense, bright cup. A ratio of 1:17 is considered a wide ratio and it yields a sweet, mild cup. 250 g of water yields enough coffee for one serving, so a 1:12 ratio requires 21 g of ground coffee, a 1:15 requires 17g and 1:17 requires 15g of ground coffee. You may see ratios sometimes written in reverse (i.e. 15:1 instead of 1:15). The reverse ratio means the same thing, it’s just a different nomenclature. If someone is using one gram of water for every fifteen grams of coffee, they’d definitely make sure to let you know!

Estimating Ratio

A gram scale is an inexpensive and very useful tool for coffee brewing and other kitchen tasks—we highly recommend that you invest in one. But scales aren’t always handy and sometimes batteries die at the most inconvenient times. Here are some guidelines for estimating coffee and water weight without a scale:

  • For finely ground coffee 1 level tablespoon = 6 grams.
  • For medium ground coffee 1 level tablespoon = 5 grams.  
  • For coarsely ground coffee 1 level tablespoon =4 grams.
  • For water, 1ml =1 gram.

Using Ratio to Change Your Brew

The chart below shows the results of six brews which each use a ratio between 1:12 and 1:17. Aside from ratio, I used the same parameters for each brew: Chemex, 300g water, 9.5 grind setting on EK43 grinder, 3 min 45 sec brew time, 205 F water.

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

The results show a nearly perfect direct, linear relationship between Ratio to TDS. As the ratio widened by 1, (i.e. 1:12 to 1:13), the TDS measurement went down by one tenth of a percent (1.67% TDS to 1.57% TDS.) The journey of the flavors is also linear and very fascinating. Starting in the middle with the 1:15 coffee, we get flavors of black tea, lemon and honeysuckle. This was the perfect brew for me with a TDS of 1.37%. Going to the 1:14 coffee, the tea and lemon flavors are present, but they are intensified and override the subtle honeysuckle note, leaving a fainter, more generic floral character. At 1:13, the tea and lemon are harsher, like a tea-bag left to soak too long in water and the floral note in gone all together. At 1:12, the tea note is very astringent and there is a salty/meaty sensation that reminds me of anchovy. Going the other direction, at 1:16, the brew is gentler overall, with the delicate honeysuckle fading to an even milder orange blossom. At 1:17 the black tea note tastes more like sweet iced tea with just a hint of lemon. I want to say that I enjoyed all of these brews, even the intense 1:12 coffee that clocked in with a 1.67% TDS, but that the best brews were those close to the 1.2-1.4% range recommended by SCAA.

Ratio at Home

If you’re interested in learning more about coffee, start by changing your brew ratio and taking notes of the strength and flavors you get. Start with a 1:15 ratio and then move it up or down based on your taste. Be willing to try a ratio that is off the well-worn path. You may find that you really enjoy it, and you’ll definitely learn something in the process.

In the next post of this series I’ll talk about changing grind size and give thoughts about using grind along with ratio to make some unique brews.

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