Perfect Cold Brew.
At Home.
1. Start with 90 grams, measure it
Typically, use a ratio of 1:9/1:10, 90 grams of coffee and 900 grams of water.
When using the cold brew studio kit, it includes 90 grams of extra-coarse coffee of your choice. This will leave the guesswork and allow you to know how it should feel.
2. Grind it right, extra-coarse
Getting the grind right is key to avoiding under- or over-extraction. When cold brew tastes sour or citrus-forward, it can point to an extraction issue; grind size, brew time, ratio, or other. That said, some coffees naturally carry citrus notes, especially lighter roasts or brighter origins. If the coffee used doesn't have citrusy notes and you taste it, it may have been underextracted. This grinding guide is very helpful!
In regards to caffeine extraction, cold brew extracts more than drip, up to 25% more in some studies.
3. 90G coarse coffee to the brewer. Pour 1150 ml water total.
Following the 90 grams of coarse coffee poured into the cold brew maker, you'll need about 1150ML of water. The optional two-step process is to help bring out flavors in coffee that are more bright, fruit oriented during the bloom pour with very warm water. If you are wanting a bold cold brew, you can skip the bloom approach and simply do one pour of 1150ML.
- Optional "bloom", pour 1 cup/200ML of 140F water, let it soak for 1 minute
- Finish off with 950ML or 4 cups of filtered water
This approach has consistently given me a TDS of 2% without sacrificing flavor. Feel free to explore or follow other ratios.
4. I focus on 1/2 - 1" space, not exact ratios
I’ve had great results focusing on where the coffee sits above the water line, 1/2 - 1 inch, rather than strictly following a ratio, e.g. 1:10 ratio.
Leaving space above the water consistently yields about 2% TDS, with great flavor. Depending on the coffee used and roast, you may end up with chocolate, nut, and malt flavors. If using something more floral with citrus, you'll get these notes. Filling the water to the top tends to give cold brew a lighter body.
5. Fresh roasted beans and gas
When using freshly roasted coffee, days after roast, you may see bubbles. This is expected since freshly roasted coffee will have gas inside. The gas that was trapped inside the bean is escaping out. If you don't see bubbles, it doesn't mean you have bad coffee.
6. Room temp. 10–12 hours. Gentle swirl once. Trash the grounds. Chill and enjoy.
Steep at room temperature, not in the fridge. Cold slows extraction and can cause under-extracted flavors. Steeping much past ~14 hours can lead to bitterness and a grainy texture.
After 1–2 hours, give it a gentle swirl (not a shake) to help water move through the grounds.
After 10–12 hours, taste it. Discard the grounds in the trash (not the sink) and store the cold brew in the fridge.
7. Taste and checking extraction, TDS
This is overkill for many, but I like data. I'll use a meter to check how much coffee was extracted. What I've learned is TDS has very little to do with favor. I've made cold brews with a TDS of 2.37% and the flavor was not pleasant. TDS of 1.67% and it felt like tea, but decent flavor.
Q: I don't have a cold brew maker at home, can I use a coffee filter?
Sure, but a regular coffee filter is going to thin out your brew. The oils that give the brew body will be missed :(
FAQ:
Q: Can I put it in the fridge instead of letting it sit overnight at room temp?
Sure, but the process is going to take longer and the flavors are a bit different. To me, the longer time didn't yield better results comparing room temp vs fridge.
Q: I don't have a grinder, what grinder do I use? Does it need to be expensive?
You don't need an expensive grinder. What I would avoid is getting a blade grinder. They are cheap, but provide inconsistent grounds. For not that much more, get a conical burr grinder.