Making coffee requires precision: ratio
AUTHOR: Daniel Moranville, KOHI
Because each coffee doesn't have the same solubility in water, whether due to the degree of roasting or the origin of the bean, the coffee / water ratio must be continuously adjusted to bring out the best in each bean. Since an espresso is subjected to about 9 bars of pressure, a small change can have a big impact. We will try here to reduce the number of trials / errors in your process.
You will need a scale and a stopwatch for the purposes of the case. Since we must have a starting point, as in every experimentation process, the ratio that is often used for an espresso is 1: 2 (1 part coffee for 2 parts water). So, if 18g of coffee is ground in my filter holder (what your machine's double filter should contain), I will extract 36g of espresso in my cup. Simple, right?
Indeed, it is not very rocket science as a formula, but what comes to confuse the cards? Time ... 1: 2 is alright, but how long does 18g of coffee take to turn into 36g of espresso? Aim for an extraction between 25 and 35 seconds to begin. Some coffees will be enhanced with faster extraction and others with slower extraction.