Why grind size and dosage matters

This blog is for all the coffee geeks out there who grind and brew their own coffee at home.  I just wanted to share an issue I once had where the coffee was dripping too fast through the filter bag and how to fix this. 

Obviously something was wrong with the coffee grind size and the coffee dosage.

The fundamentals of coffee brewing

The following two factors have a direct impact on the coffee extraction:

  1. Coffee grind size - coarser the coffee, faster the pour, and vice versa for finer size.
  2. Coffee dosage - less coffee dosage, faster the pour, and vice versa for higher dosage.

It is important to adjust the above two factors to a point which can bring out the optimum balanced flavour from the coffee. 

Anything below the point is called under extraction, meaning not all the elements are extracted from the coffee and the taste is weak.

On the other hand, when the coffee is over extracted, more substances are extracted from the coffee and will taste bitter and unpleasantly strong.

What to do if your coffee is dripping too fast

An article by Coffee Brewing Center (CBC) provided the solution to this problem.

In the 1960's, CBC investigated the best way to brew black coffee, and they came up with the following findings:

  • The ideal dosage ratio is around 60grams coffee / 1L water, and
  • The strength of coffee should be between 1.20 to 1.45 percent of solubles concentration.

This explains why my coffee was dripping too fast. I was using only 50g / L, hence the coffee was under extracted and tasted weak.

After I adjusted the dosage and grind size, I then used a total dissolve solids (TDS) meter to check the percentage of solubles concentration. The readings were around 1.35% for all coffees, within the ideal parameter.

Recommended formula

Some of us brew our own coffee at home or work, and may question what is the best formula to get the ideal flavour.

I recommend to start with 60g/ 1L water, and eventually adjust the variables to achieve your preferred cup of coffee.

It's in applying this same formula that we have decided on using 12g of coffee in our drip coffee bags and in determining the grind size. 

For more information on the CBC study, please check out the following link:

https://www.coffeechemistry.co m/quality/brewing/brewing-fund amentals

Hope you found this information useful!


Happy brewing,


Back to Blog