So I know the accepted practice for cold brew is to do a coarse grind, and to brew somewhere between 8-24 hours depending on whether you're doing it at room temperature or in the fridge.
But is this really necessary? Could I just use a finer grind and brew for less time? I'm asking because when you grind coarse, you end up having to use a lot more coffee beans (mass) than you would for the equivalent volume of any other type of coffee.
For context, I'm using a coffee sock which is just a glorified reusable coffee filter, so I don't think that grind size is going to impact filtration that much.
You can use a suis vide and make it in 2 hours instead.
The whole volume/coffee mass trade-off is a bit misleading. Espresso has a much higher ratio, and cold brew is by taste and strength somewhere between filter coffee and espresso. Mixing cold brew half and half with sparkling water is a nice way to bulk it out if you want a greater volume of coffee.
Oh good, now I just need to acquire a suis vide :)
I do generally mix the cold brew half and half with filtered water. I do have to say, I love sparkling water of all kinds, but I tried this with sparkling water and was not a fan, haha.
I basically make cold brew coffee in a French press that I stick in the water bath at 65 degrees c for two hours and then decant it into a new jug I stick in the fridge.
Just try it. When I started making cold brew I did a bunch of experimenting with grind size and brew time. I dont grind much different from when I make hot coffee, but I found the brew to improve up to 24h or so. Anything less than 18h or so was not acceptable. One thing you can try if you want to speed things up is a hot bloom before adding the rest of the brew water and moving it to the fridge.