Hi, I have a ratio problem. I have Breville BES870XL Barita Express. My grinder is Set to 4. I’d like to use double-size single wall filter and I use RO water. I have tried to make it with 17gr of grounded coffee. I used a leveler and a hand tamper. The pressure gauge was at a 1 o clock location. unfortunately, when I measured the extraction it was 56gr or 2oz and my extraction time was 25 seconds. Color and cream didn’t have any problems. But why the ratio is almost 3.1x and not a 1:1.5 or 1:2 ratio?
For every different coffee, you need to tweak it to maximize the flavor, texture which you want. Maybe you need a hotter brew temperature or maybe a finer grind. There is no right or wrong way for this, just find whatever works for you and then repeat it. If it was easy everyone would do it.