The roast of your coffee is generally dependent on your personal taste, or that of your customers. Some people will stick to dark roast no matter what they hear from coffee elitists and no matter what single origin light roast pour over they taste. Some people will have nothing less than the latter. Roasting to a certain degree, however, is preferential in some circumstances aside from taste. For the most part, for example, you’re going to want a light roast for single origins/pour over brews; this enables the more dynamic flavor profile that those are generally meant to highlight.
What about for cold brew? The latest trend is cold coffee, which allows for bulk preparation and lower acidity– but does it benefit from one roast over another?
Most coffee experts seem to agree that a medium roast is your best bet for a cold brew batch. Why is this?
In the first place, one of the main selling points for cold brew is the lower acidity. Light roasts, as a rule, tend to have higher acidity than other roasts.
You can take this however you want; the decision is yours. Since light roasts have higher acidity, you could choose them for your cold brew blends/batches. Cold brewing will lower that acidity and the dynamic flavor profile may have intriguing results after the brewing process. This could be potentially beneficial for fruitier beans: cold brewing may result in a fruity coffee without the acidity that is characteristic of citrus.
On the other hand, if cold brewing is specifically being used for its lower acidity, utilizing a higher-acidity roast is kind of counter-intuitive. A light roast is generally a more complex flavor profile and that will get lost in a cold brew. This is likely why medium roasts are recommended for a cold brew. Some even recommend using a dark roast because of the clouding of flavors that tends to occur when you cold brew. A dark roast won’t lose quite as much because it starts out with a more generic flavor.
For experimentation purposes, I would suggest trying all three if you can. I would imagine that a light roast with a distinct flavor profile would benefit from losing the acidity while retaining its interesting profile. You want to experiment because the effect of cold brewing could take away the good characteristics. A dark roast may come out too heavy and even darker tasting. A dark roast may also be the most consistent throughout the process, no matter how it is brewed.
That’s why I say do some tests. What you like is up to you and your clientele.
A medium roast is probably the safest bet because you’ll still have whatever flavor profile you selected, the reason you chose those specific beans, without too much acidity or unpredictability. A medium roast will, in my opinion, less boring and potentially bitter than a dark. I also always recommend a light roast to be pour over or drip as often as possible so that those delicate flavors can sing through.
As a coffee roaster, you are in a powerful position when it comes to cold brew. There isn’t a lot on the market right now specifically tailored to cold brew. Few roasters are trying to figure out the best blend and roast for this slow-brewing method, even as more and more coffee shops begin to feature it. Any are just using what they have on hand, roasts for drip coffee, French presses or even espresso.
The problem with this is that these blends are blended and roasted specifically for hot brewing. Cold brewing is different; it has a different effect on the flavor profile and mouthfeel of a coffee. Tailoring a blend and roast to this process will set you apart from your competition definitively.
Cold brew is not iced coffee; it is brewed at a cold temperature for a long amount of time. The beans will spend more time in the water than in any hot brew. They will also be extracted purely based on water solubility and not through heat, or steam pressure as in the case of espresso. You’re going to get different things, as in, just the flavor elements that are water soluble.
The extraction process is important when considering roast. For example, hot brewing does not allow as much of the “char” and burnt elements to absorb from a dark roast as a cold brew will. This is a con to using a dark roast: if the roast is particularly dark, and not roasted to be a good quality dark roast, the cold brew will suffer; it will exaggerate that burnt quality.
It will also be beneficial for extraction to experiment/consider steeping time. With a light roast, the bean’s cellular degradation is lower than with darker roasts, which means it’ll take longer to break down and extract those coffee elements. If you’re cold brewing a light roast, you will probably get better results from a longer brew time.
Finally, even though I’m personally hesitant about it, I have read that a colder brew may do really good things for a single origin coffee. This is because heat causes the bean’s flavor and caffeine molecule to evaporate, essentially. This is why single origins are typically roasted ever so lightly. In a slow, cold process, these elements will remain and, potentially, be enhanced or exaggerated. This could be a good version of exaggeration, as opposed to what could happen with a burnt bean. Single origins tend to be pricier and rarer so I would know a little more about what cold roasting does to specific roasts before experimenting with them. Because the flavors tend to be way more dynamic, it could backfire; but, if you’re trying to get an edge on the market, it could be very well worth a shot.
And when you figure out your perfect cold brew roast, you can get just the right packaging to explain why it’s the best, what the process was, where the beans came from, if they’re a single origin, and what roast you chose and why. You can put cold brew in bold, colorful, customized letters when you purchase your packaging supplies through PBFY.com. They have the best packages for storing coffee and the offer the latest labeling technology at affordable prices!