Two methods of brewing coffee cold have become popular. One method Cold Brewed Coffee uses an immersion style of brewing and the other Cold Drip Coffee uses a slow drip brewing system. Cold Brew Coffee has more floral flavors than Cold Drip Coffee but Cold Drip Coffee has a richer body.
Cold Brewed Coffee is an immersion style brewing. Cold water and ground coffee are mixed together, allowed to steep for hours or days and then the grounds are filtered out. The resulting brew is very strong so it has to be cut with either hot or cold water.
Cold brewed coffee is popular because it is less acidic and has a smoother mouth feel than hot brewed coffee. It is also convenient since it can be stored in the refrigerator and then served either hot or cold. The downside is that it has higher caffeine and less flavor than the same coffee hot brewed.
Cold brew can be made with DIY materials or you can buy cold coffee brewers.
If you want to DIY coarse grind your coffee and add it to a jar or pitcher. (french press will work too). Then add cold water on a ratio of one gram of coffee to 8 grams of water. Leave the jar in the refrigerator for 12 to 24 hours. The longer the stronger and the more acid. If you used a french press push the plunger and decant. If you used a jar or pitcher pour the slurry into a brew basket with a filter. You can also use cheese cloth. Repeat if you want less solids in the coffee.
If you made enough for one cup, add hot or cold water to dilute and enjoy. If you make more you can store it in the refrigerator for about 2 weeks..
If you don’t want to DIY there are Cold Coffee Brewers available on the market. Three of the better ones are: Hario Cold Brew Bottle, Mizudashi Cold Brew Coffee Pot, and the OXO Cold Brew Coffee Maker
Cold Drip Coffee
Cold drip coffee is made with three vessels. The top vessel contains cold water. In some techniques the top vessel contains ice which is allowed to melt. The second vessel contains ground coffee. The cold water is allowed to drip though the ground coffee and exits through a filter into the bottom vessel. This can take anywhere from 1 to 24 hours. Cold drip coffee is usually served over ice like an espresso-shot.
Cold drip coffee is almost acid free with a creamy, thick body. It is excellent when made with light roasted flavorful coffees.
Cold drip coffee requires a drip tower. Drip towers are available starting at around $60. More elaborate towers with hand blown glass can cost up to $10,000. Some of the commercially available brewers are the Cold Brue, Dripo cold brewer, Yama Glass Tower and the Nispira Ice Cold Brew Dripper
Once you have a drip tower you can use the following recipe. Grind 1 gram of coffee for every 10 grams of water or ice. Use a normal pour over drip grind. Load the ground coffee in the second vessel and the ice/water in the top. Set the drip to about 1 drip per second. Check the drip about every two hours until all of the water is gone.
You can store cold drip coffee in the refrigerator for up to two weeks.