By now most of us have probably heard of something referred to as the Golden Rule.
As a quick refresher, the objective of the Golden Rule is to brew a double shot of espresso (2.5oz) in 25 seconds. One variable is the fineness and consistency of your ground espresso; another is tamp pressure. Thirty lbs of tamp pressure is what most experts recommend. There is also a consensus that any tamp pressure that is consistently applied each and every time will work. Consistency is the key word here. Whether it is 30lbs or 50lbs of pressure, the key component is to use the same pressure every time. You can, then, adjust your grind setting to follow suit and get the perfect extraction.
Remember as a rule of thumb it should take an average of twenty five seconds to brew a double shot of espresso. To demonstrate the impact tamp pressure can have on espresso extraction, I usually have customers apply both a very forceful tamp, as well as an extremely light tamp. The difference in the extraction time can be amazing. Literally, you can go from an extraction time of ten seconds, with a light tamp, to an extraction time of forty plus seconds, with a heavy tamp, all using the exact same grind setting. If an excessive amount of pressure is needed to slow the flow down to twenty five seconds, the espresso is probably ground too coarse. Likewise, if the extraction process is taking too long, exceeding twenty five seconds with a light tamp, the grinder should be adjusted to deliver a courser grind.
Keep in mind that everybody’s palate and preferences are different. Some people will use a very heavy tamp pressure and brew their espresso for fifty or sixty seconds; they will adamantly argue this method produces the best tasting espresso. I also know people who always brew a long shot, 3oz-4oz, and will argue that this is the only way to make good espresso. I’m more of an authentic Italian-style espresso maker, but can appreciate that everybody’s preferences are different. In the end, you should use the method that best suits your tastes. So practice, experiment and enjoy!