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Food - Drink
The Possible Reason Your Freshly Ground Espresso Tastes Sour
Making espresso at home is convenient with the help of an espresso machine, but the process isn't foolproof. Sometimes your homemade espresso can taste sour or bitter, and this puzzling side effect is mostly likely a result of the way you grind your coffee beans — specifically, the size of each individual ground.
In the study "Systematically Improving Espresso," researchers found that espresso suffers when the coffee grounds are too fine or too coarse. Specifically, when the grounds are too fine, their dense consistency hinders the hot water's journey through the beans, resulting in a bitter or sour taste due to subpar flavor extraction.
For great espresso, Above Average Coffee recommends evenly-ground coffee particles that are around 0.8 mm in size. Of course, making sure every coffee ground is this exact size is impossible, so simply set your coffee grinder to medium-fine, don't go any finer, and do some trial and error to make adjustments for your ideal espresso.