This article describes basic variables for espresso extraction. Learn this and you can create a perfect espresso recipe. Goal of the espresso recipe is to create perfect balance between these variables.
Soaking up beans before full pressure is applied. Helps to prevent channeling in coffee. It’s generally recommended to perform pre-infusion. Infusing coffee can modulate taste. General example for complex testing found online here.
Best result is achieved, according to research, by following TCP rule, which means “Time to cover porta-filter”. Therefore stop pre-infusion right after all beans were soaked in and filter is starting to pour the coffee.
Pre-infusion is particularly helpful with higher altitude coffee. This allows to grind finer and then use pre-infusion to pre-soak beans to allow decent extraction without choking extraction with too fine grind.
In general temperature settings can help to bring out more flavor in your recipe. Generally speaking white roasts can withstand higher temperature cause they are lightly roasted. Longer the coffee extracts, more contact with head which might contribute to brunt taste. Water acts as solvent, higher the temperature more deeper the extraction.
Lowering the temperature can therefore reduce extraction and prevent bitter taste and increase acidity. While increasing temperature can create richer flavors and develop more body.
Most important variable. Finer the grind size, slower and more intense the extraction is. Every coffee has a breaking point from both ends. Watery or sour coffee tends to be under-extracted while bitter and astringent is sign of grinding too fine.
Generally speaking more increasing dose can contribute to more body and sweetness, therefore intensifying extraction. Overdoing this can on the other hand can decrease acidity and make coffee taste sharp or bitter.
Lowering the dose can bring out more acidity but on the other hand can decrease body and create watery or weak coffee brew.
For Sage Barista Pro recommended dose for double shot basket is between 19 to 22 grams.
Ratio between grind dose and extracted coffee.
For example 1:2 ratio is 19g of ground coffee would equal to 38 grams of liquid coffee (Yield).
- Lighter roasts are usually brewed at to 1:2 ratio or even higher
(more watered down)
- Darker roasts tend to go low as 1:1.5
Espresso extraction Time
Longer the brew time more in contact with head which can lead in to overcooking, if too high temperature is set. At the same time longer the time more extraction. White blends, lightly roasted coffees tend to be pulled longer and usually brewed with less body, e.g. more watered down which highlights more fruitiness and sweetness. Time is not a variable but a result of setting other variables. We need to always create recipe (dial-in) to taste, not to time.
Coffee produced in higher altitude should be extracted with higher temperatures.
- Lower elevation (under 1500) coffee use rather lower temperature and less contact time with head.
- Higher elevation (1500 and higher) will require higher temperatures and longer contact time with head.