WHY COLD BREW?
There are three common reasons that cold brewed coffee is growing in popularity: 1) lower acidity, 2) approachable flavors, and 3) convenience.
Lower Acidity: There are many who cannot drink hot brewed coffee because the acidity upsets their stomachs and causes acid reflux, but they can drink cold brewed coffee without any stomach upset. Because of this, many make claims that cold brew has low acidity. Based on the best available research, this may be an overstatement. A more accurate statement would be that cold brewed coffee (compared to hot brewed coffee) is lower in certain types of acids because it avoids extracting specific acids and solubles that are only extracted at higher temperatures, which appear to be the cause of acid reflux and the like. If you are interested in cold brewing coffee because of the lower acidity, we would recommend using medium-dark to dark roasts as they are lower in acidity than lighter roasts and we would recommend starting out with coffees known to be inherently lower acidity such coffees from Brazil, Indonesia, Sumatra, India, etc.
Approachable flavors: Cold brewed coffee is often described as the gateway for many into the world of specialty coffee because it often has very approachable flavors such as chocolate, caramel, and nuttiness (depending on the coffee). Cold brew is often described as high in sweetness, low in bitterness, and smooth. The criticism of cold brew by some is that it is often generic in its flavor profile, but this is false generalization. If you are interested in a cold brew with broader flavors, consider fruity natural processed coffees or consider infusing cold brew with fruits during the brewing process.
Convenience: Rather than having to wait for hot brewed coffee to be brewed, one of the appeals of cold brew is the simplicity and convenience of being able to brew enough cold brew at one time to have on hand in the refrigerator as desired for up to one to two weeks.
HOW TO COLD BREW?
The most simplistic, low cost, and forgiving way of brewing cold brewed coffee is the immersion method. At the most basic level, all you need for this method is: ground coffee, an airtight container (e.g., plastic container, mason jar, French Press), cool to cold water, time, and a means to filter the brewed coffee. Cold brewing coffee does not have to be complicated or expensive. It can be both, but does not have to be in order to achieve great tasting results at home. Cold brewing coffee involves learning how to manipulate the following variables: 1) time; 2) grind size; 3) brew ratio of ground coffee to water; and 4) temperature.
Temperature: While there are some deviations such as “hot-blooming,” cold brewing involves the use of room temperature or colder water hence the name “cold” brewed coffee. The coffee can be left on the counter or placed in the refrigerator to brew, but needs to be stored in the refrigerator once brewed.
Grind size: The most common recommendation is to use coarsely ground coffee for cold brew. This is because course ground coffee is more forgiving and less prone to over extract compared to more finely ground coffee. It is also less prone to clog filters when straining the cold brew. Our recommendation is to start with coarse ground coffee, but experiment with the grind setting to discover how it impacts flavor.
Time: A good starting point is 18–24 hours to allow cold brew to steep, but experimenting with lessening the steep time to as few as 12 hours is an easy way to add some variety in the flavors you can extract with cold brew. Just like with tea, steep time will impact the strength, body, and the flavors in the cup. Too short of a steep time will result in under extraction and sourness. Too long of a steep time will result in over extraction and bitterness. How you brew cold brew will place some limitations on whether you can sample the cold brew as it brews to determine if you would prefer it to brew longer.
Brew Ratio: When it comes to cold brew, there are two common approaches: 1) making cold brew concentrate and 2) making ready to drink strength cold brew. The most common starting ratios for cold brew concentrate is a 1:4 or 1:5 ratio such as 1 gram/cup/etc. of coffee to 4 grams/cup/etc. of water. For example, if we are using 60 grams of coffee and want a 1:5 ratio, then we need to use 300 grams or 300 milliliters of water (60 x 5 = 300). The main benefits of cold brew concentrate is 1) it takes up less space than a ready to drink strength, 2) it can be used in milk-based drinks and still allow for the coffee flavor to be tasted, and 3) it can be diluted in water to achieve the desired drinking strength. The most common starting ratios for ready to drink strength cold brew is 1:10 to 1:11. For example, if we are using 60 grams of coffee and want a 1:10 ratio, then we need to use 600 grams or 600 milliliters of water. Probably the best online brew ratio calculator we have found that allows you to interchange different units of measurement is https://honestcoffeeguide.com/tools/coffee-to-water-ratio.
Three Filter Options: While there are a lot of options on the market for brewing cold brew, the goal of this post is to discuss entry level, lower cost options, which do not sacrifice quality. For those who brew cold brew in an airtight container where the coffee is loose, you will need to use some type of filter to separate the coffee and brewed coffee. Two low cost options that you may already have in your home is a fine mesh metal sieve or a bleached coffee paper filter placed in the sieve, a pour over brewer, or even your drip coffee maker brew basket. Using only the metal sieve will result in a heavier body coffee with more fine particles (i.e., sediment) in the cup. Using a paper filter will result in a much cleaner cup of coffee with slightly less body and less coffee oils. For those using a French Press, we recommend you take the following steps before pressing the plunger: 1) Take two spoons and scoop the coffee that is floating on the top and discard it, and then use the spoon to gently stir the top of the top as this will cause the coffee to sink; 2) Wait a minute or two and then press the plunger to the top of the coffee, but not below to prevent stirring up the sediment in the coffee; 3) If you don’t mind some slight sediment in your cup, gently pour the coffee into an airtight storage container such as a mason jar or cup and enjoy; or 4) Pour the coffee from the French Press into some object containing a paper filter for a much cleaner cup. The final option, which in blind tasting we prefer, is using Alto Cold Brew filter bags. With the medium sized Alto filter bags we offer on our website, you place the ground coffee inside the bag (we recommend no more than 100 grams), pour the desired amount of water over the ground coffee, stir it to ensure all the ground coffee is wet, tie the bag, and the let it steep in an airtight container. Not only do we prefer the flavors of the cold brew using the Alto filter bags, but the added benefit of them is the ability to sample the cold brew as it brews as the grounds are contained in the filter bag.
We would love to hear your feedback on this post and your experiences with cold brewing coffee.