When my grandmother made coffee, she used the scoop that came with the 5 lb. Hills Bros can and did what Hills Bros told her to do. She used one scoop for each mark on the side of her percolator. She didn’t weigh the coffee, she didn’t weigh the water, she didn’t know what the water to solids ratio was. She did what she was told. It worked for her, my grandfather liked her coffee.
There are all kinds of coffee scoops on the market. They are not all the same; some are teaspoon sized, some are tablespoon sized, many claim to hold two tablespoons. They are all inaccurate.
Measuring by Volume
At 6 am in the morning facing a day of work and a morning commute, using the scientific method to make coffee is not an intriguing idea, that is the reason that coffee scoops are so popular.
Remember the old joke about which is heavier one pound of lead or one pound of feathers? Well, which is heavier one scoop of medium roast ground Kona coffee or one scoop of dark roast ground Kona coffee? I don’t know the answer, but I know they won’t be the same.
Some years ago, we had a Hula Daddy coffee scoop. It was supposed to scoop the perfect amount of coffee for 6 fluid ounces of water. However, a scoop of coarse ground coffee weighed 10 grams and a scoop of fine ground coffee weighed 11 grams. It wasn’t much of a difference in weight, but it made a difference in taste.
When you measure coffee grounds by volume you are ignoring the differences in density between coffees. A scoop of a more dense coffee will extract more than a scoop of a less dense coffee. If you are using the same coffee every morning and the same number of scoops, the flavor and body of your coffee won’t vary by much. But if you switch coffees you will have a completely different coffee/water ratio even though you use the same number of scoops.
At 6 am you have two realistic choices 1) ignore the differences because you are still half asleep anyway or 2) find the ratio you like and use the same coffee every day.
Measuring by Weight
The reason that chefs use scales to measure ingredients instead of volume measurements (e.g. measuring spoons) is because volume measurement is inaccurate and not replicable.
You know that a gram of ground medium roast Kona coffee weighs the same as a gram of ground dark roast Kona coffee. If you add the grounds to the same amount of water, you will get the same ratio of water to solids in your coffee cup and about the same mouthfeel.
If you have the time and want to be a great coffee brewer, you need to use a scale. Kitchen scales will work. You can get them at the local big box store or Amazon for as little as $20.
Use 10.6 grams of ground Kona coffee for each 6 fluid ounces of water. You can weigh the water but drinking water density doesn’t change, so fluid ounces will work. However, if you are a purist, six fluid ounces of drinking water weighs 177.4 grams