How To Measure Coffee (Hint: Ignore scoop sizes and tablespoons)

Different Roast = Different Mass

In the specialty coffee world, evenness and precision rule all. We have the tools to measure everything; from the total amount of dissolved solids in a cup of coffee, all the way down to coffee grinds particle distribution. Yet with all these high tech measuring and analytics tools, our most important and valued is a simple digital scale.

When brewing coffee, we measure our ingredients in grams. This is more reliable and precise than using volume based measurements like cups or tablespoons.

Here’s why: All coffees have a different mass.

When coffee is roasted, it undergoes multiple changes. One of the many changes, is to the moisture content of the bean. A green coffee-- that is a coffee before it has been roasted, will have a moisture content of somewhere around 11% (1).

This reduction in moisture content leaves the beans weighing around 15-20% less than they did when they were green.

During roasting, this moisture content drops to somewhere in the 3-5% region (2). This is because the water within the beans structure turns to steam and is released. This reduction in moisture content leaves the beans weighing around 15-20% less than they did before they were roasted.

Generally, the darker the coffee is roasted, the lower the moisture content will be. Therefore, a darker coffee will weigh less than a lighter roasted coffee.

Why the Amount of Coffee Matters 

A big part of making great coffee is knowing how much of the good stuff to use. If too much coffee is used, the brew may be under-extracted. This coffee will taste sour, won’t have much sweetness, may taste a little salty and will lack any real depth. On the flip side, if we don’t add enough coffee, the resulting brew will taste weak and thin, flat and watery.

“Over extracted coffee is dry and bitter and under extracted coffee is sour and empty (amongst other tastes)” - Matt Perger, Barista Hustle

There are many schools of thought as to exactly how much is the ‘correct’ amount, and there is no right and wrong answer, just preference (some will swear otherwise). While it is largely a matter of option, most coffee professionals, including the SCAA (Specialty Coffee Association of America) have agreed at a starting point of around 60 grams of coffee per 1L of water (60g/L).

We can implement this using brew ratios.

How To Use Brew Ratios 

A brew ratio is a simple guide as to how much coffee and water to use. It gives us an easy recipe to follow and serves as a good starting point for various brews.

A brew ratio looks like this: 1:15, 1:16, 1:17, etc.

A brew ratio of 1:15 means; 1 part coffee to 15 parts water. A 1:15 ratio may be 20g of ground coffee, brewed using 300g of water. This will produce an approximately 300ml cup of coffee.

To use brew ratios, you can go one of two ways:

  • Start with the amount of coffee you want to use, or;
  • Decide how much coffee you want to make (...and then figure out your brew ratio based on that). 

Let's do an example for each option, using a French Press brew.

Starting with the amount of coffee you want to use

Let’s say we want to use 20g of coffee. Multiply that by our brew ratio, which in this case is 15:

20g x 15 = 300 (grams of brewed coffee)

In this case, we’ll be using our scales to measure out 20g of coffee to brew with a French Press. We’ll set up our press on the scales, add the ground coffee, press tare on the scale, then pour water into the press until the final weight is 300g. 

Decide how much coffee you want to make 

I prefer to do it this way: decide how much coffee you want to make, then figure out your brew ratio based on that. The first challenge is deciding on how much coffee you want to make. The standard size of a cup of coffee is full of differing opinions (3), so for simplicity's sake we are going to say 10 ounces (300ml).

So we want to make a 300g cup of coffee, which will be approximately 300ml in the cup. To work out the brew ratio and the amount of coffee to use for 300g of water, we’ll go:

300 (grams or milliliters of water) ÷ 15 (our chosen brew ratio) = 20.

20 grams of coffee is how much we’ll add to make our 300ml cup of coffee.

Brew ratios to use for each brew method

As a starting point:

  • 1:15 brew ratio is good for most immersion brew methods
  • 1:17 brew ratio is good for most pour over methods

Again, these ratios are a starting point. If you like your coffee a little stronger in flavour, add an extra gram of coffee or three. If you prefer your coffee lighter, use a couple of grams less.

How much coffee for 6 cups?

This is one of the most common questions around this topic, and if you’ve read this far, you should easily be able to work this out using brew ratios.

If we use 10oz or 300ml as our standard cup of coffee from the above example, we will need 1800ml (or grams, same thing) of coffee. Using a brew ratio of 15, this is how it would look on paper:

1800ml ÷ 15 = 120. Therefore, we need 120 grams of coffee to make 6 cups of coffee (at 10oz per cup). Easy.

Here’s at table for those lazy skim readers among us. For a 10oz cup of coffee using a standard 1:15 brew ratio:

10oz CUPS (300ml)

Amount of coffee 

Amount of water

1

20g

300ml

3

60g

900ml

6

120g

1800ml

8

160g

2400ml

10

200g

3000ml

How to measure coffee using scales

The only accurate way to measure the amount of coffee we are using, is to weigh it. While there are other ways to get an approximate amount of coffee; we’ve learned these are flawed due to coffees’ varying mass.

“A scoop of coffee can vary in density depending on many factors, including the variety, size, and roast of your beans.” - Kelly Sanchez, Blue Bottle Coffee

Follow these steps to measure coffee with scales:

  1. Place the scale on a flat even surface and turn it on.
  2. Place the container you want to put your beans into on the scale.
  3. Press ‘tare’ (this will set the scale back to zero).
  4. Add your desired amount of coffee to the container (refer to brew ratios above in regards to how much coffee you should add).
  5. Make sure you are as precise as possible

Always measure your coffee before grinding, not after. If you measure your coffee before grinding, you’ll have the exact amount ready to be ground. If you grind then measure, you’ll either have too much and will have some coffee left over (which will be wasted) or you won’t have enough and will need to grind more!

how to measure coffee grounds using a scale

Consistency = great coffee. Use a scale

Final Thoughts

While there are other methods of measuring coffee, (cups, coffee scoops and tablespoons) these are all volume based measurements. This makes them ineffective. They all lack accuracy.

As we’ve learned in the section above, a coffee’s origin, varietal, process and roast degree can affect its weight greatly.

If we’re using a coffee scoop, we may think we’re getting the same amount of coffee; (1 scoop) but in reality, from one coffee to the next, we may be increasing or decreasing the amount we’re using by 25%. This can make a huge difference and can lead to under or over extraction. Not to mention the fact that without scales, we’ll have no ability to repeat a great cup.

In summary - if you’re serious about coffee, use a coffee scale. Happy brewing!

FAQs

How many grams of coffee in a tablespoon?

There is approximately 5 grams of ground coffee per tablespoon. As mentioned earlier, however, you should not rely on tablespoons as an accurate way to measure coffee, but it will get by.

How many tablespoons in a coffee scoop?

A standard coffee scoop holds 2 tablespoons of level ground coffee.

What should I look for in a scale?

In a scale, you should look for a fast reaction time and accuracy to 0.1g. While these are the two most important things you should look for in a scale, having one which is waterproof, has an inbuilt timer and is USB rechargable are also definite pluses.

What’s the best scale for measuring coffee?

The best coffee scales, or at least the scales chosen by most specialty cafe’s and roasters, are made by Acaia. Acaia utilise some very nice technology involved in their scales. This tech includes bluetooth connectivity, a flow rate meter and brew guides. Brewista, AWS, Jennings and Hario also do decent scales, which are absolutely worth checking out here. We reviewed the best coffee scales for home baristas in this guide - check it out if you need one.

Do I need a coffee scale?

Yes, you do need a coffee scale if you want to make great coffee every time your brew. While you can certainly get a decent result in the cup using other measuring tools, what you won’t get is repeatability. If you make a bangin’ cup one day, you won’t know exactly how much coffee or water you’ve used, which means you probably won’t be able to recreate that cup the following day.

Can I measure coffee without using scales?

Yes you can measure coffee without scales, but you can not accurately measure coffee without using scales. If you do find yourself needing to make coffee, and worst case scenario - you’re without scales, here are a few tips on how to do it in the most accurate way possible.

  • Decide if the coffee is light (light brown), medium (darker brown but not oily) or dark (very dark and oily) roast.
  • A standard tablespoon of light roasted coffee should weigh around 7 grams.
  • A standard tablespoon of a dark roasted coffee should weigh around 5 grams.
  • A standard tablespoon of medium roasted coffee will be somewhere in the middle.

References

  1. Pashley, T. (2018, May 10). Roaster Guide: Why Is Green Bean Moisture Content Important? Retrieved from https://www.perfectdailygrind.com/2017/08/roaster-guide-green-bean-moisture-content-important/
  2. Chemical Changes During Roasting. (2015, April 27). Retrieved from https://www.coffeechemistry.com/quality/roasting/chemical-changes-during-roasting
  3. Rodriguez, A. (2018, October 05). The Problem With Coffee Cup Sizes: 7 Miles. Retrieved from https://www.sevenmiles.com.au/editorial/problem-coffee-cup-sizes/
Alex
 

Alex is the Founder and Editor of Homegrounds.co. He is passionate about brewing amazing coffee at home, and teaching others to do the same.

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