Wellllll........ Firstly, I'm not a barista, I'm not a scientist, I'm not even any good at math, so all of my information is probably shit.
I looked around and found out that gram of arabica coffee beans can have anywhere from 10 to 18 mg of caffeine in it. I decided to just take 14 and roll with it.
In my cold brew process I'm weighing out 10oz of beans which is about 283.5 grams worth (which I then coarse grind and soak overnight). If we take the 14mg/g number and plug it into my spreed sheet, its 3969 mg of caffeine.
I'm told the caffein has a really easy time leaching out and, considering 14 is just a ballpark, I'm just gonna pretend the 3969 mg of caffeine covers the 10 ounces I'm grinding and leave it at that.
After the cold brew process is done, this turns into about 24 floz of concentrated coffee. Which gives us 165.3 mg of caffeine/floz.
This means that when I make 12floz cup of coffee (my normal amount) then I should be using about 1 floz of concentrate and it'll be waves hands about 165mg of caffeine.
I didn't know this though, and I read somewhere that I should be doing a 1:3 dillution of coffee concentrate to water. So I was using 4 floz at first, which is 661mg of caffeine (probably).
I knew that was too strong just by how my body reacted to it, so I went to 1:4 which ends up being 496mg of caffeine.
Well, assuming I measure it right, which is an awful assumption.
I've just kind of been eyeballing it in a 2 cup measurer I have, trying to get it around 1/3 of a cup...but probably over filling because it always looked like so little coffee to me.
Well, it's not a little, it's apparently a more than fair amount 😅
Going forward I'm going to make the concentrate into a bigger bottle of coffee and measure out a quarter cup against 5.5 cups of water (4 oz : 44 oz). Hopefully it goes well, we shall see...