What Is The Perfect Ratio Of Coffee Grounds To Water?

Aloha Friends! We continue our quest for the skills to make the best cup of coffee and to answer the frequently asked questions we get here on the farm. Today, we are talking about ratios. 

Almost every day, I am asked how much coffee to use and while I feel we have discussed this before, let me lay down a definitive answer and try to address the complexities that exist.

The first thing to remember is that if you are scooping your coffee and not weighing it, you are getting a slightly different cup of coffee every day. Now, that is not to say that with careful scooping and precise water measurements you can’t get a good cup of coffee, just that scooping is imprecise, the density of coffee changes by roast, and many people are not taking the time to be exact day after day.

If you fall into the category that says “I’m too busy to weigh my coffee and scooping is my only option,” let me get you started on the simple rule of thumb used by home coffee makers for centuries. One to two tablespoons per 6 ounces of water.

My natural question here is…which is it? One or two tablespoons? Well, that depends on your personal preference and you have to try varying amounts until you hit on the one that makes you smile.

Another problem is that very few Americans these days use 6-ounce cups. The Tall at Starbucks is 12 ounces. The Short is 8 ounces. The average mug size is 8 to 20 ounces.

The standard for cups on the carafe of drip makers is 6 ounces. So, if you fill your carafe to the 4 cup line carefully, my grandmother would say, “one heaping tablespoon per cup (that’s 4) plus one for the pot” (5 heaping tablespoons total).

Now let’s do a little math. If I favor a 16:1 ratio (This is the standard ratio in the specialty coffee world with some exceptions)

If a heaping tablespoon weighs about 6 grams (according to my scale) and my grandmother put 5 heaping tablespoons in the pot, she would have 30 grams of coffee grounds to 680 grams (4 cups) of water. That is about 22:1.

No offense to grandma, whom I love dearly, but that is not going to satisfy a hardcore coffee drinker like me.

If she had put 2 heaping tablespoons per cup plus the one for the pot, the math says she would have a near 13:1 ratio which will be a very thick cup of coffee. Possibly better for staining the deck than drinking.

If she did 8 flat tablespoons for the 4 cups without adding the extra for the pot, she would be closer to the desired ratio. So, can we say 2 flat tablespoons per 6 ounces of water? I think you are going to be close.

Remember though, that the longer you cook your coffee (Dark, French roast) the lighter and more porous it becomes. That means that if you are scooping a French Roast as opposed to a Medium Roast, you are getting very different ratios.

Consistently good coffee requires consistency. So, what is the formula if I am going to weigh my coffee?

Formula Breakdown

First, know that you can get a simple coffee scale on Amazon for around $15. If you have a small kitchen scale it should also be adequate.

No matter what method you are using to make your coffee, measure out the water and weigh it. Convert it to grams. Google has an amazing calculator that converts anything to anything.

Now, divide by 16. That is the amount of coffee grounds you will use.

I often use 320 grams of water (about 11.3 ounces) to 20 grams of coffee. It always comes out perfect. (320 divided by 16 is 20)

Back to the drip-maker for a moment. If you are making 4 cups of coffee which would be 24 ounces as measured in the carafe, that will convert to 680 grams of water.

Dividing that by 16 we get 42.5 grams of coffee.

If you measure in this way you will always have a consistent and flavorful cup of coffee without wild variations.

If you try this and find that you don’t like this ratio, there are many who prefer a 15:1 ratio but the same rules apply.

You can also do this in reverse. Say you are at the end of your bag of coffee and it’s not quite enough for your usual method. Weigh the coffee and multiply by 16 and that will give you the amount of water to brew with.

To sum up, whether you are using 2 flat tablespoons per 6-ounce cup or weighing your ratios, there is a precision required in making coffee so that you have an excellent cup day after day. If you become mindful of that only, it will be a big step forward in your coffee journey. After that, personal preference reigns supreme. Once you find that preference, the ability to repeat it consistently will be your biggest challenge.

Enjoy!

Matt Carter

Matt Carter is a retired teacher (1989-2018), part-time musician, farmer, and currently manages Greenwell Farm’s Tour and Retail Store Operations.