How to Scale Your Batch Size Up or Down: The Correlation Between Grind Size and the Amount of Ground Coffee Being Brewed

Why grind size matters?  For longer than I care to admit, I struggled transitioning from brewing smaller amounts of coffee at home on various pour over drippers to larger batch brews because I did not understand the correlation between grind size and the amount of ground coffee being brewed (i.e., the dose).  When I used the same grind size that was perfect for brewing single serving amounts of coffee while trying to brew as much as five or six times that amount of coffee, the results were not great.  It wasn’t until I started grinding much coarser that I started to see an huge improvement in the flavors in the cup.  The lesson I learned was that I had to be willing to be flexible and adjust the grind size depending on how much ground coffee I wanted to brew.

How you can apply this at home?  Let’s say you have a “12-cup” drip coffee maker.  All drip coffee makers have a minimum and a maximum amount they are designed to brew.  Let’s say you have really perfected brewing the minimum amount but have guests coming over and want to brew the maximum amount.  You will have to grind coarser to brew a larger amount of coffee.  Let’s say you have perfected brewing the maximum amount but now want to brew the minimum amount.  You will need to grind finer.  The reason that grind size is so important for filter coffee brewing such has pour over brewers, home drip coffee makers, or large commercial batch brewers is that the grind size in conjunction with the depth of the ground coffee is largely what determines how fast and how even water is able to flow through the bed of ground coffee.  

What if you purchase preground coffee?  Since there is a correlation between grind size and the amount of ground coffee that can be brewed well in any brewer, you will have to experiment with brewing different amounts and find what amount is optimal for your brewer.