Cold Brew Brewing Guide - Overview
by Nic Tracy
Spring is in full swing and cold brew season is on the horizon, so I’ve got a general brewing guide in store for you today! For those of you already making cold brew, just consider this a refresher on the subject or a fresh perspective if you’re brewing differently than I suggest; for those of you considering getting in on the action, feel free to interpret my brew guide as general guidelines rather than hard-and-fast rules. Everyone likes their cold brew a little different than the next individual and should tweak their recipes accordingly (it's why cold brew and nitro competitions are so fun!).
I tend to think of brewing cold brew like any other method of brewing coffee: a ratio of grounds to water while considering temperature, time, turbulence, grind size and roast freshness. Cold brew is typically prepared with courser grinds, but several shops have found successful recipes using finer grinds and adjusting their brew times down accordingly. However, we trend towards the courser side of the spectrum in an effort to increase filtration speed, brew clarity and shelf life. The aforementioned ratio can be tricky to determine with this much volume; in lieu of a giant scale for weighing your gallons of water like some kind of giant pour over, we've found a pretty handy trick at Brewista for ensuring that your brew fits the SCA-recommended 1:17 ratio by weight. It turns out that a ratio of 1 pound of coffee to every 2 gallons of water is just under that ideal ratio. Two gallons of water weigh 16.68 lbs, meaning our "1:2" ratio is actually 1:16.68 by weight. Considering the cooler brewing temp, longer brewing time, and courser grind, we end up with a similar extraction to a good pour over (around 1.32-1.35% TDS). Let me backpedal and say that while cold brew has been traditionally brewed as a concentrate, we've found that brewing it as a ready-to-drink (RTD) beverage rather than something to be cut with water later yields some incredibly delicious results. However, for those of you who appreciate the convenience, cost benefits, or flavor of a concentrate, we suggest a "1:1" ratio, or 1 pound of coffee for every 1 gallon of water (a 1:8.34 ratio by weight). Cut this with equal parts water to concentrated cold brew when you serve it to achieve a normal consistency and flavor profile. With regards to brewing in our systems specifically, the Cold Pro 4 has a maximum fill of 4 gallons while the Cold Pro 2 has a maximum fill of 7 gallons. Considering that the coffee grounds will retain a small portion of that water, the yield will be roughly half a gallon less than the amount of water initially used. Use the handy visual below as a quick reference!
I like allowing for a little bloom time as well with my cold brew; using a ratio of 3 parts water to 1 part coffee, I’ll gently stir the brew bed to ensure there are no dry clumps to ensure even extraction. After five minutes or so, I’ll add the rest of the water. Cold water permits a less pronounced bloom than hot water, so the benefit here is more about the even extraction than it is for releasing carbon dioxide in my experience. This is one of the reasons a few shops implement a “hot bloom” into their cold brew process, but some would argue that introduction of heat into any stage disqualifies the end product as cold brew (however, it is important to note that there is no hard definition for cold brew and a counterargument can be made that since the hot-bloomed coffee is still brewed cold, it can still be classified as cold brew). We may do future articles on alternate and unconventional recipes, but for today let’s stick to the basics. For brew time, if I'm brewing an RTD at room temperature (around 70 degrees Fahrenheit) I'll typically do 16 hours, but if it's colder (our lab is attached to our warehouse, so it can get pretty cold in there in the winter months) I'll potentially go all the way up to 21 hours. If I'm brewing a concentrate, I'll up the brew time by about 2 hours vs. what I would do for an RTD. Of course, we always suggest testing your brew at different times until it tastes the way you and your customers like it!
Bean freshness is the final factor I’ll bring up to consider in your recipe; while cold brew can be a great way to use up older beans that would have otherwise gone to waste, we’ve found that using fresher roasts usually yields a more delicious final drink. However, much like your decision to brew an RTD or a concentrate, this decision is largely informed by the economics of your business model and what works best for your situation. A fresh single origin or specialty blend RTD cold brew can be marketed and sold as a premium beverage (step it up even further by serving it on nitro), while a concentrated brew of older beans can turn a significant volume at a lower production cost and price point. In either case, if your shop has embraced the increasing trend of coffee mocktails, you can also utilize your cold brew in mixed drinks! There are some fantastic recipes out there for both alcoholic and virgin beverages, so you can get in on the action whether or not your shop possesses a liquor license. This is a great way to diversify your cold brew lineup and expand your customer base!
We could discuss any of the variables mentioned above at length (and will certainly do so in future articles this year), but this is a widespread, surface-level collection of the key factors I pay particular attention to when brewing cold brew at the Brewista headquarters here in Cheyenne. There are a million different iterations of the end product that can be achieved by altering any of these variables along the way, and I'm sure that if you're already doing cold brew you've got your own unique way of approaching it. If you want to share your recipes with me or discuss any of these factors further, please send an email over to email@example.com and I’ll get back to you as soon as I can!
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