Classic Espresso Blunder #2: Using Too Many Beans in a Blend

What may be the most overlooked aspect of espresso blends is the fact that the bean composition of any given espresso shot will rarely match up exactly with the bean composition of the overall blend. For example, if a bean is exactly 50% of an espresso blend, that bean will NOT be 50% of EVERY espresso shot. In some cases, the bean will be over-represented; in others, it will be under-represented.

The chart above measures the probability that a given bean in an espresso blend will be accurately represented in the 110-120 beans needed to produce a double shot of espresso.

[Readers who have taken Dr John’s espresso blending class at Coffee Fest and/or read his seminal blending article in “The Book of Roast” may recall a numerical table that he presented to convey this same point. We used data from that table to produce this chart.]

HOW TO READ THIS CHART

The X-axis (i.e. 10-50) measures the percentage of a blend that a given bean represents. The Y-axis (i.e. 30-90%) measures the odds of that bean being accurately represented in a double shot of espresso.

When a bean is 50% of a blend, it will be roughly 50% of a double shot nearly 75% of the time. The rest of the time, your espresso shots will have either too much (or too little) of that bean.

As the chart shows, things become much more inconsistent when a bean is just 10% or 20% of the blend. In both cases, the bean will be under- or over-represented in the MAJORITY of espresso shots. 

WHAT DOES THIS MEAN FOR YOUR ESPRESSO?

Your espresso will taste much more consistent if your blend- whether created by you or supplied by a roaster- consists of a small number of beans. If your blend has five, six, or nine (yikes!) beans, rarely will two consecutive shots taste the same.  

THE TAKEAWAY:

  • Ideally, the espresso blend should have only two or three beans.
  • Each bean should be a large percentage of the blend. Having one bean that is only 10% or 20% of the blend just leads to inconsistent espresso shots. Better to have each component at 30% or higher.

Learn More: Visit Josuma’s Espresso Blending educational resources.