You don’t want to find out the hard way
In the ever-evolving world of the coffee business, the hot trend that is here to stay is actually not hot at all. It’s cold brew, the next evolution of iced coffee. Until the spread of cold brew, coffee shops only sold hot coffee and hot coffee poured over ice creating a watered down beverage that has about as much coffee as it does melted ice. Maybe even less. When it comes down to cold brew or iced coffee, cold brew wins. Not to mention that cold brew has twice the caffeine content of regular iced coffee. It’s all well and good for people in the coffee industry that cold brew has picked up so much steam, this means that, as the New York Times reported, coffee sales are now higher in the summer and baristas aren’t twiddling their thumbs come summer-time hoping for a devoted coffee drinker in need of a fix no matter the medium.
The problem with iced coffee that spawned the cold brew obsession is that even if the cafe takes extra care to refrigerate the hot-brewed coffee so that you don’t end up with sad coffee water, hot-brewed iced coffee tends to be more acidic than even hot coffee that isn’t chilled. That’s pretty damn acidic. The Times also noted that, “While hot coffee can be volatile, changing in flavor at different temperatures, cold brew is relatively stable, which makes it particularly well suited to being packaged and sold as ready-to-drink.” That’s why when you go to the refrigerated section of your grocery store you find rows of glass bottles touting different styles of cold-brewed coffee from an array of places. The only truly unfortunate part about cold brew is the price. You end up paying upwards of $4 for a small, which is some serious coffee inflation. Even the bottled stuff ain’t cheap, and trust me when I say that the more commercial cold brew is not worth the space in your fridge (I tried them).
The process for making cold brew is not difficult which is why if you like to drink coffee year-round you should just start making your own cold brew at home. But first, a word of caution that might ruin your cafe-going experience forever. Sorry. Cold brew, much like iced tea, does not have a super long shelf life. It may not be as good of a medium for mold as tea, but cold brew will mold if you don’t keep it refrigerated and consume it within a week or two. I know this because myself and the entire staff at the cafe I was working at got scolded via text about unwittingly serving our customers moldy cold brew. In our defense, it was the dead of winter and barely anyone was ordering cold drinks. For those few unfortunate souls, they were the victims of a rotational system of steeping coffee in four gallons of water for 12 hours at room temperature and then leaving the sealed buckets at room temperature until pouring it into a serving container that sat at room temperature.
As for shelf life, no one would recommend keeping cold brew, even a concentrate, for longer than a month. Some sources would not recommend longer than two weeks, but cold brew in a concentrated form keeps a little longer. Grady’s, the popular New Orlean’s-style bottled cold brew instructs consumers that it will stay fresh for a couple of weeks and that as you drink it you should also size down the container so there is less air in the bottle to oxidize the coffee and leech the flavor. Stumptown says their bottled cold brew will last about 2 weeks. The general consensus is consuming it within the first week is the best way to enjoy cold brew, bottled or otherwise. The moral of the story for you is don’t ever leave your cold brew at room temperature unless you want to open it one day and find weird little collections of oily, greenish patches floating on top of your batch.