In an earlier post (”What Fractionation Teaches You about the Ideal Size of an Espresso Shot”), we outlined an experiment called Fractionation. Pulling an extra-long espresso shot (3+ ounces using an amount of ground coffee appropriate for a double shot), breaking it into six (or more) glasses, and tasting each portion is a great way to demonstrate and understand coffee chemistry. The typical takeaway: A double shot of espresso that is two ounces (or less) will taste far better than a larger “lungo” shot.  

There’s also a second part to this experiment. One that a coffee house can use to determine how large they want their double shots of espresso to be.

A fractionation experiment, like the one pictured above, will produce the following six half-ounce glasses:

• Glass #1 (the left-most glass in the photo): Very sweet. Heavy mouthfeel.
• Glass #2: Sweet. Good mouthfeel.
• Glass #3: Bitter. Some depth of flavor. Not watery.
• Glass #4: Very similar to Glass #3.
• Glass #5: Very bitter. Weak. Watery.
• Glass #6 (the right-most glass in the photo): Even more bitter. More watery.

Since the typical response to Glasses #5 and #6 is “Yuck,” we can safely discard those two. The main takeaway of the original Fractionation Experiment was that those have no part in a delicious espresso. 

With the rest, we can incrementally build an espresso shot until we find the combination that we like best:

• Shot A:  Combine Glass #1 and Glass #2.  Swirl to combine. Take a small sip (or two) to taste.
• Shot B:  After tasting Shot A, add Glass #3 to Shot A. Swirl to combine. Take a small sip (or two) to taste.
• Shot C:  After tasting Shot B, add Glass #4 to Shot B. Swirl to combine. Take a small sip (or two) to taste.

What most cafe owners/baristas find is that the whole is greater than the sum of its parts. Although most people find the sweet, viscous liquid in Glasses #1 and #2 far more enjoyable than what’s in Glasses #3 and #4, the combination shots (Shot B and/or C) end up being smoother, rounder, and more balanced.  

With our own Malabar Gold Espresso, customers who have run this experiment typically conclude that the best espresso shots are Shot B (roughly 1.5 fluid ounces), Shot C (two fluid ounces), or something in between (1.75 fluid ounces).