Repeat this process, slowly adjusting the grind setting each time, until you are able to achieve 34gr of espresso, from 17gr of grinds, in between 20-30sec. If you are using the barista express, do not fixate on the “Espresso Range” marked on the pressure gauge. It is widely agreed upon that the best shots are actually pulled from 12 o’clock and onward on the dial.
(Tip: if you cannot achieve this flow rate because you are at the min or max grind setting, you will need to adjust the internal burr setting to give yourself more range)
Now that you have achieved a reasonable flow rate, it’s time to learn the fundamental concepts of espresso extraction that will help you turn your drinkable shot, into a GREAT shot. Espresso extraction has 2 key pillars, that form the foundation of how a shot tastes. Strength, and Extraction.
Extraction refers to how much coffee-goodness the water was able to pull from the grounds. Over-extracted coffee can come across as bitter, or astringent, while under-extracted coffee will often come across as sour or unpleasantly acidic.
Strength, refers to how much coffee-goodness was extracted, RELATIVE to how much water was pushed through. In the cup, this will relate to the body, or mouth feel of the shot. Too high a strength can come across as thick or muddy in texture, while too low strength will be thin and watery. Take a moment to taste your shot again, and try to determine where it falls with respect to BOTH the extraction, and strength.
This chart is a great way to dial in to your individual preferences, and for each individual coffee. Note that if you fall into one of the corners, you may need to adjust both your grind setting AND yield to reach your desired result. I recommend only changing one variable at a time, and always remembering to go into programming mode on your Breville when pulling a shot after an adjustment.
In general, darker roasts will be easier to extract, requiring a more coarse grind, and less water. Lighter roasts on the other hand, will require you to grind finer, and have a higher yield to fully extract.
This brings us to shot temperature. If you aren’t quite able to reach your perfect combination of strength and extraction, temperature is the final tool in your arsenal. Raising the shot temperature will allow you to achieve a higher extraction, without further reducing the strength of the shot. This is commonly needed to properly extract lighter roasts. Oppositely, darker roasts may require you to lower the shot temperature in order to reduce bitterness without lowering the overall shot volume.
The one thing to understand about dose, is that it only determines how MUCH espresso you can make at a certain brew ratio.
For example, if you want to be brewing at a typical 1:2 brew ratio, a dose of 16gr will yield 32gr of espresso. A 20gr dose? That’s right! 40gr of espresso.
Your dose size is really only limited by the filter basket. The larger the basket, the larger the shot you can probably manage to pull. You also don’t want to go too low with dose, as this will create too much distance between the group head and you coffee puck leading to pooling. All Breville’s other than the dual boiler and oracle machines use a slightly smaller 54mm size portafilter, meaning that if you want to play around with dose, I’d caution against going much higher than 18gr, and slightly lower doses can actually be beneficial. What’s important in terms of dialing in, is to pick an appropriate dose for your machine, and keep this number fixed throughout the rest of the process.
Yield, in combination with the dose, creates what is often referred to as a brew ratio. How much coffee (the dose) to how much espresso (the yield). Changing this ratio, plays with the balance of “extraction” and “strength” of the shot.
As you pull a shot, you are continuously adding more water, therefore diluting or reducing the “strength”. But you are also simultaneously increasing how much coffee goodness you’ve pulled from the beans or “extraction”. Obviously, there are limits to this. If you let a shot run for a minute, by the end you would still be reducing the strength by pouring more water into the cup, but no-longer be getting any more extraction. The beans have nothing more to give. This chart helps to explain this. As you can see, as the extraction percentage gets higher (we move from left to right), the strength decreases at an ever accelerating rate.
So that means there is a sweet spot. That sweet spot will depend on personal taste, again there’s no ONE answer. A shorter ratio like 1:1 will be very strong, but may taste sour or underextracted to some. A long ratio like 1:3 or will be weaker, but some find it is sweeter and more balanced. You have to experiment. I recommend starting at a 1:2 as a standard midpoint, and adjusting from there to individual taste preferences. A good way to understand how the flavours change as a shot progresses is to do an exercise known as the “Salami Shot”. What you do is switch to a different glass every 5 seconds as your shot runs. Let the shot run extra long, maybe 40 seconds. This way you can taste what flavours are added to the shot at each stage of the extraction, and start to fine tune your palatte to whether you like the flavours of a longer or shorter shot.