This is awesome in an overengineered way, but if you want to make cold brew the normal way it's very easy. Basically you make it using a cafetière/French press/Bodum[1] using cold tap water in the fridge overnight (probably put some cling film over it), then press it and run it through a drip filter. The secret (if there is one) is to use fine ground coffee like you would use for an espresso rather than coarse ground (like you would use for a normal drip coffee or French press). It's very easy and very lovely. Just don't skimp on coffee.
If you use a French press for cold brew, be aware that the harder you press, the more bitter it will come out.
I use a $5 nut milk bag instead, it lets me brew way more at once; I do 1/4 kilo grounds with 2 liters of water. It also has the benefit of reducing cafestol, which makes it healthier, according to some.
Probably. To be honest I just find it convenient to use a French press as a cold brew maker and first-pass filter, because it is IMO easier to keep clean than a nut milk bag or coffee sock.
>the harder you press, the more bitter it will come out
Huh? I don't plunge until after it brews, and the purpose of the plunge is just to keep the water out of the grounds from that point forward, to (essentially) stop the brewing process. Or so I thought
Plunging pushes your coffee through the metal filter. Pushing harder pushes the coffee through the filter with a higher pressure. Higher pressure pushes particles past the filter more easily than lower pressure. Coffee particulate has a tendency to make coffee more bitter.
Anything that gets more small particles past your filter will add to your coffee's bitterness. This can happen when using a ground coffee that has a lot of fine particles, or if you agitate when you pour/plunge.
I don’t know anyone who’s jumping up and down on the plunger or doing anything more than pressing it slowly. Have to imagine the coarseness/evenness of your grind is a 10x bigger factor in that regard
>I don’t know anyone who’s jumping up and down on the plunger or doing anything more than pressing it slowly.
Also my reaction the first time someone tried to tell me to plunge slower.
>Have to imagine the coarseness/evenness of your grind is a 10x bigger factor in that regard
100%. Plunge speed makes a minor difference at most, and only then when you have a suitably coarse and even grind.
If you want to play with the concept I think the best way is to prep a press, but instead of plunging the filter into the coffee before pouring, press it only to the top of the liquid and pour, allowing gravity to pull coffee through the filter. Pour a small cup like this, then press the rest of the way and pour another cup.
I have a french press for camping, it's fine but when I want that first cup of coffee and it's cold and rainy outside you better believe I'm not pressing it slowly.
Given the grind has already been specified as an espresso-level of fineness (we're talking about a cold brew recipe), most of the grinds are going to be able to get through the metal filter.
The original suggestion of plunging slowly and gently is entirely sensible, since it's the only variable available in the context.
One thing I'll mention is that cold brew doesn't need to be put in the fridge to "brew". It can be left out on the counter at room temperature. As a result, this takes the brew time from 24 hours to about 12 hours.
More detailed recipe here https://www.uncarved.com/articles/cold-brew/
[1] UK/US/French name but you know the thing with the plunger