Cold brew bottle
A bottle with a built-in filter for steeping tea in cold water for hours in the fridge. It sounds like a compromise and it is not: cold water pulls a genuinely different set of compounds out of the leaf, and the result is sweeter and rounder rather than simply weaker.
- Capacity
- 500 ml to 1.5 l
- Material
- borosilicate glass or Tritan, steel or plastic filter
- Origin
- modern
- Best for
- green and yellow tea, and Darjeeling
What it is
Usually glass or Tritan with a filter in the neck or a removable strainer basket. There is also a laboratory-looking tower version, a metre or so tall, where iced water drips slowly through a bed of leaf, which produces excellent results and does not fit in a fridge.
What it does to your tea
It changes the extraction profile rather than just slowing it. Cold water pulls out roughly 53 per cent of the EGCG that hot water does, and caffeine likewise extracts poorly cold, which is exactly why cold brew tastes less bitter and less astringent. But catechins are not one thing: the non-gallate ones, EGC and EC, come out readily in cold water, and measured total antioxidant activity in cold-brewed infusions can be equal to or higher than hot-brewed. So the common claim that cold brewing extracts fewer catechins is half right at best. Less of the bitter fraction, more of the others, and a different profile rather than a smaller one.
What it suits
Green and yellow tea especially, and Darjeeling, which is unexpectedly good cold. Roasted oolong and puer work but need longer. Anything whose appeal is astringency will lose it.
How to use one
Use about 50 per cent more leaf than you would hot, since the extraction is less efficient. Fill, refrigerate, and give it two to three hours for white and green, three to four for oolong, and about five for puer and black. Take the leaf out when it is ready rather than leaving it in the fridge for days.
How to choose one
A basket you can lift out beats a filter built into the neck, for the same reason a french press wants decanting: you need a way to stop. A wide mouth makes it possible to get wet leaf out and a brush in.
Care and cleaning
Wash properly and dry. Cold-steeped leaf sitting in a bottle at fridge temperature is a mild microbiological risk in a way hot brewing is not, so this is the one piece here where a rinse is not enough.
What people get wrong
Using the same leaf quantity as for a hot brew and concluding cold brew is weak. It is under-leafed, not under-powered. The other is leaving it steeping for a day because it seemed fine at three hours.
What it is made of
Sources
- cold water extracts roughly 53 per cent of the EGCG that hot water does, while non-gallate catechins such as EGC and EC extract readily cold and total antioxidant activity can be equal or higher Comparative studies of low-temperature green tea infusion, including Food Chemistry (2025) on optimising low-temperature brewing