Brew ratios and recipes...
are often in the forefront of specialty coffee conversations. It's a road, or maybe more so a rabbit hole, that I traveled down to a huge extent when I first dove into coffee. Espresso gets even more complicated once you start using fractions for ratios as well. I've been so focused on chasing those perfect numbers (i.e. yield and time) that I've cruised through almost an entire bag of coffee trying to find that pot of gold at the end of the rainbow. That is not only a waste of coffee and time, (both of which are not unlimited resources) but also can be extremely frustrating.
This brings me to my opinion on ratios and recipes. Now, I'm not saying they are bad or even useless. They are useful starting points, and if you work for a cafe or roasters you should be aiming for the ratios and recipes that they have laid out as a standard. Yet, as a home barista, or just a coffee professional making coffee at home, its okay to approach the process in a more exploratory way.
The way that I do this is rarely aiming for those perfect numbers, and mainly focusing on extraction time and blonding. Even though some feel blonding isn't the ideal way of determining the end of extraction, I do believe with most coffees show color cues that can lead to a better understanding of what the shot is "done". Although this also can vary on the palate of the person tasting it, so I recommend toying with this. Don't let ratios and recipes pull you away from the enjoyment of the exploration process in making a great shot of espresso. There are no right or wrong answers here, just your tastebuds.