I’ve been playing with cold brewing and changing the technique and recipe slightly with each batch. Here are some of the things you can control when brewing coffee:
- Grind (Turkish – Coarse)
- Grinding Method (Burr, Chop, Pound, Roller Grind)
- Roast (Cinnamon – Spanish)
- Species (Arabica vs. Robusta)
- Bean Source and Freshness
- Water Quality (Hardness, Purification Method, etc)
- Method (Drip, Pressurized Percolation, Boiling, Steeping)
- Pressure (Drip – Espresso)
- Brew Temperature (Ice Cold – Boiling)
- Water to Grind ratio
- Equipment quality, cleanliness
- Brewing Duration
- Agitation During Brewing
- Repetition (Brew, Filter, Replace Coffee, Repeat)
- Filtering
- Dilution
- Preparation (Milk, Sugar, etc)
I’ve been changing one or two with each batch and recording the results. Some of these factors, especially Roast, Species, and Grind will make a big, noticeable change to your cup of coffee with any of the traditional hot brewing methods. What I’ve found with cold brewing is that almost none of them matter! I can’t tell the difference between the cheapest store brand crap and single-estate Kona once it’s been cold brewed. Duration is one of the few exceptions – if your goal is to brew coffee without extracting the bitter flavor I don’t recommend going past 12 hours.
Next I’ll be looking at Repetition, inspired by Black Blood of the Earth.