The coffee brewing ratio
Ok FBCR friends. Here is my new year's resolution. I am going to do my best to write a new blog every week for all of 2016! I've got a large backlog of topics I want to write about and I will have some more time this year. I hope you will join me in a year of coffee education. Also, if any of you has any suggestions for what I should write about, what you want to learn more about, e-mail me, firstname.lastname@example.org.
Today's topic is on getting the water-to-coffee ratio correct. I have learned, there is a big disconnect from the average coffee drinker and the professional coffee industry. Making coffee is somewhat like following a recipe, except that it is not. To me it is more like a chemistry experiment. And once we stop thinking in terms of recipes it will be easier to understand.
So let me first explain why making coffee is not like a recipe and why doing this creates unnecessary confusion. In a recipe, the measurements are volume based. One cup of flour, a half cup of sugar, a teaspoon of salt. The recipe assumes that all flour (assuming you are using the type that the recipe calls for) weighs about the same and that any minor variations are not going to affect the outcome of the recipe. Imagine if the recipe instead said, 120 grams of flour, 80 grams of sugar, and 4 grams of salt. This would be a weight-based recipe. This method is more accurate but, for the average batch of cookies, entirely unnecessary. The problem is, the same is not true for coffee.
A level coffee scoop (2 tablespoons) will yield anywhere from 7-11 grams of coffee depending on the original density of the bean and the level of roast. Darker roasted coffee is less dense than a medium roasted coffee (thus you need to use more volume to get the same weight). The opposite is true of very light roasts. So, I prefer to use a basic kitchen scale and throw out the volume-based measurements all together.
THE RATIO. 15 water: 1 coffee.
Enter the ratio. A unit-less expression that measures the relationship of two variables. In a ratio, it has no practical meaning until it is assigned a unit, but it can be applied to any unit you like so long as the two items you are comparing use the same unit of measure.
I like to use grams for most of my coffee brewing. A gram is small enough to give great accuracy with your coffee weight, but not so small that you end up working with giant numbers for one cup of coffee. So, if I use my 15:1 water to coffee ratio and I want to make one 12-oz cup of drip coffee, I would first need to convert ounces to grams. 1 ounce of water is equal to about 28.35 grams. So my 12-ounces of water would weigh roughly 340 grams. And if I divide this by 15, I get 22.7 grams of coffee, which I would round to 23 grams. Here is the end result, 23 grams of coffee beans for a 12-ounce cup of coffee.
This can also be applied to a full pot of coffee. When you are making larger amounts, you can switch your units to ounces to keep the numbers small, or you can stick with grams for accuracy. You have to first see what your coffee-maker defines as a cup (it can be anywhere from 4-6 ounces depending on the manufacturer). Say you want to make 6 cups of coffee, and your coffee maker says that each cup is 5 ounces. You will need roughly 30 ounces of water. Apply the ratio (divide 30 by 15), and you find you need 2 ounces of coffee (or 57 grams).
As you can see, there are really only two steps that you need to remember to apply the ratio in any situation. 1. Determine the weight of the total water you are brewing with. 2. Divide this number by 15 and use that as your coffee bean measurement. Also, if you don't like my 15:1 ratio you can try changing the ratio to 17:1 or 13:1. Both of these are in the accepted range for drip coffee based on the Specialty Coffee Association of America's guidelines. But, I would not advise going past these points as you run the risk of over- or under-extracting the coffee.
There are lots of things you can do to increase the quality of your brew; buy freshly roasted coffee, grind just before brewing, use good tasting water, etc. But I think the brewing recipe is the most fundamental and will allow you to get the best out of any coffee that you come across. Happy brewing!