Light roast washed Ethiopian that makes a lovely floral V60. Cold brewed it at 1 to 8 in the fridge for eighteen hours, coarse grind, filtered through paper, then diluted one to one. It came out flat, slightly papery and with almost none of the fruit. Is the bean wrong for cold water, or am I doing something wrong with the grind and the time?
Numbers from a weekend of being annoying about this. Same medium roast, 1 to 5 concentrate, room temperature, tasted a sample at 8, 12, 16 and 24 hours. Eight was thin, twelve was pleasant, sixteen was the best of the four with actual sweetness, twenty four had gone woody and slightly savoury. So there is a window, it is not longer is stronger forever, and mine closed somewhere before the twenty hour mark.
Ask yourself how old the concentrate was when you judged it. Cold brew keeps in the fridge for a week or so but it is not static, and a batch I loved on day one tasted exactly like your description of papery by day four. If you brewed on Sunday and formed your opinion on Wednesday, brew a small batch and taste it within a few hours before you blame the bean.
The bean is fighting you. Cold water pulls out much less of everything, and it is especially bad at the acids and aromatics that make a light washed Ethiopian worth drinking, so what you get is the boring middle of the coffee. Light roasts are also physically harder, so they give up less at any given time.
Two changes: brew at room temperature for twelve to fourteen hours rather than eighteen in the fridge, and use a medium roast with some body to it. Fridge brewing is slower and gentler, which is exactly the wrong direction for a bean that is already reluctant.
Room temp for fourteen hours with a medium roast and it is a completely different drink. Fridge cold brew was basically a very slow way of making nothing happen.
Cold water extracts less per unit time, so you compensate with grind and time, not with more coarse and more waiting. Go medium rather than coarse and filter twice, once through mesh and once through paper. Coarse plus long is the recipe that gives you the papery nothing you described.
My mistake was filtration. Used a nut milk bag because it was in the drawer, ended up with a sludgy concentrate that kept extracting in the fridge and tasted more bitter every day. Now I strain through mesh to get the bulk out and then run it through a paper filter, and the concentrate tastes the same on day five as it did on day one.
@immersion_ivy · 3w ago · 3 replies
Different tack. If what you love about that Ethiopian is the floral acidity, cold brew is the wrong process for it, full stop, and no amount of tinkering will get it back. Brew it hot straight onto ice instead. Same V60, same dose, but replace about 40 percent of the brew water with the equivalent weight of ice in the carafe and brew the rest hot at your normal recipe. You get the aromatics because you extracted hot, and it chills instantly so they do not cook off. That is the drink you actually want.
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@rollback_rae · 3w ago
Agreed, and this is the honest answer rather than the popular one. Cold brew is a process for making a smooth low-acid concentrate. If you chose a bean specifically for its acidity, you are paying for something and then removing it.
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@frosting_fixer · 3w ago
Worth adding that the ice has to be weighed as part of the total water, otherwise you end up with a very strong brew that gets watered down by melt at an unpredictable rate.
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