Yesterday I came across a Toronto area blogger, StDan, who has picked up his own cause for finding some of the best espresso served in his fine city of Toronto: Espresso Hunt: Little Italy. Naturally, even at this early stage, he noted the following (familiar) problem: “most places put too much in it”.

Yes, the infamous overextraction problem. Making good coffee is as much a science as some of the finer points of cooking. To simplify matters a bit, brewing coffee is largely about the science of temperature and pressure… and time. The goal is to extract the most ideal flavor and aroma components from roasted, ground beans while leaving behind much of what isn’t so delectable.

  • Old, stale beans? You won’t have much “good” coffee flavor to work with in your cup.
  • Too hot? (Brewing temperature is ideally just below boiling.) You’ll scorch the beans and impart more of an ashy flavor.
  • Not enough pressure? You leave too much of the “good” coffee behind — largely gushing water through coffee’s water-soluble elements that can taste quite nasty on their own. (This is perhaps the #1 problem with home espresso machines.)

On the other hand, pull too much water through your shot of coffee and it’s a little like using your tea bag three times too many. Except it’s far worse than just diluting your espresso. Letting more water pour through the coffee “puck” in the espresso machine, you draw out an excess of these water-soluble elements — resulting in more caffeine (contrary to conventional wisdom, a proper espresso has less caffeine than a typical cup of coffee), more bitter flavor elements, and yet a watered-down taste.

In my experience, overextraction is the #1 problem with espresso in most of North America. Hands down. In part, this is probably due to drink expectations from a culture accustomed to the Super Big Gulp®. So ironically, in the name of customer satisfaction, we are served more of something that’s far inferior. (“Smaller is better” has never resonated with our consumer culture.)

And if a café can’t get a handle on the extraction, any enjoyment of a thick crema that sticks to the sides of pre-heated cups is secondary…