How long does cold brew last in the fridge?

The data

There isn’t much. Two peer-reviewed studies followed plain, refrigerated cold brew over weeks, and only one of them tasted it.

The tasting study. Lopane, McGregor and Rieck brewed one Brazilian coffee three ways: cold brew made in the fridge, cold brew made at room temperature, and hot drip chilled right after brewing. They bottled each in sealed 120 mL glass bottles and kept them at 7 °C for 42 days. Bacteria never showed up. Every sample stayed under 25 colony-forming units per mL at every check [1].

The flavor moved anyway. pH fell significantly in all three by day 42. Five trained tasters scored the coffee as less bitter over time and found more sour-fermented and papery-stale notes [1]. The authors conclude that in the fridge, flavor rather than microbes limits cold brew’s shelf life. They say the cause of the change is unclear. The day-by-day scores appear only inside the paper’s figures, so we describe them rather than re-plot them.

The bacteria study. Polanco-Estibález and colleagues steeped a commercial Arabica/Robusta blend for 17 hours at 4 °C and stored it in small sealed bottles for 90 days [2]. Untreated, its bacteria, yeast and mold counts stayed low for the whole 90 days. Its pH dropped by up to 0.24 units in the fridge, against 0.7 at room temperature. They didn’t taste it.

Then they spiked some bottles with E. coli, Listeria and Salmonella at about ten million cells per mL. None of the three grew in the fridge, and none disappeared. All three were still alive after 60 days at 4 °C [2]. Five of the seven authors work for a maker of high-pressure processing equipment, which is what the study set out to test. The untreated results reported here don’t depend on that.

	Tasting study (2024)	Bacteria study (2023)
Brew	4 h at 4 °C, 1:14, one coffee	17 h at 4 °C, Arabica/Robusta blend
Stored	Sealed 120 mL glass, 7 °C, 42 days	Sealed small PET bottles, 4 °C, 90 days
Bacteria (clean samples)	Under 25 CFU/mL throughout	Low throughout
Added pathogens	Not tested	Survived at least 60 days, no growth
Flavor	Less bitter, more sour and stale by day 42	Not tested

The official number

The only official figure in the neighborhood is the FDA Food Code’s limit for refrigerated, ready-to-eat food that restaurants make and hold: at most 7 days at 5 °C (41 °F) or colder, with the day it was made counted as day 1 [3]. It’s a general food-safety rule and doesn’t mention cold brew.

Sealed containers are a different problem

Shelf-stable canned cold brew is classed as a low-acid product, so it has to be processed to prevent botulism [1]. Cornell’s Food Venture Center says there is no scientific information showing cold brew is safe in reduced-oxygen packaging such as nitrogen-infused cans [4]. That warning is about sealed, low-oxygen containers. A jar in your fridge is a different case, but the warning is still a good reason not to keep cold brew sealed at room temperature.