Cold Brew Tea, Bottled: A Guide to the Filter-in Range
To make cold brew tea, add roughly 10 g of loose leaf tea per litre of cold water to a filter bottle and refrigerate. Green tea steeps in two to three hours, black and oolong in four to six, herbal and fruit blends in six to eight. Cold steeping extracts far fewer tannins than hot brewing, so the tea tastes sweeter and won't turn bitter if you leave it longer. It keeps about three days refrigerated.
Iced tea in this country usually means hot tea that's been left to go cold, and it tastes like it. Stewed, tannic, and needing a lot of sugar to be drinkable.
Cold brewing is a different process with a different result, and it's almost impossible to get wrong.
Why it doesn't go bitter
Tannins are what make over-brewed tea harsh and drying, and they need heat to extract efficiently. Take the heat away and they largely stay in the leaf, while the sugars and aromatic compounds come out slowly.
So a cold-steeped tea is sweeter, rounder and much more forgiving. Leave a pot of hot tea for twenty minutes and it's undrinkable. Leave cold brew tea for an extra two hours and it's marginally stronger, and that's all.
Steeping times
Roughly 10 g of leaf per litre, which is about two heaped teaspoons. Overnight in the fridge covers almost everything on that list.
Which bottle
The Filter-in Bottle at £27.50 holds 750 ml, has a mesh strainer in the neck and a sealed cap, so it can lie flat in a fridge door. It also comes in olive green.
The Filter-in Carafe at £40 holds a litre with the strainer built into the spout, so the leaves stay in the carafe as you pour and keep infusing. Better if you're serving rather than carrying, and it comes in grey too.
For a desk or a bag, the 400 ml portable bottle at £40 is the one to take with you.
Making it
1. Add the leaf. Loose leaf gives a much better result than bags, which are usually filled with dust.
2. Fill with cold water, straight from the tap is fine.
3. Cap it and refrigerate for the time in the table.
4. Pour. The strainer holds the leaf back.
You can leave the leaves in, unlike cold brew coffee. The tea will keep strengthening slowly, but it won't turn bitter, so most people just let it be.
Keeping it
About three days in the fridge, shorter than cold brew coffee. Green tea starts losing its brightness after a day, so make less of it more often.
Rinse the silicone seal separately now and then. It's the part that holds onto smells, particularly after anything with hibiscus in it.
Prefer a hot pot? The ChaCha Kyusu Maru at £32 is the everyday teapot to pair with this.
Frequently asked questions
How long does cold brew tea take to steep?
Two to three hours for green, four to six for black and oolong, six to eight for herbal and fruit blends.
Can you use tea bags in a Hario Filter-in Bottle?
You can, but loose leaf gives a noticeably better result. Bags usually contain broken dust that over-extracts.
How long does cold brew tea last in the fridge?
About three days. Green tea is best within a day or two.
Is cold brew tea less caffeinated than hot tea?
Generally yes. Caffeine extracts more slowly in cold water, so a cold-steeped tea tends to be gentler.
Can the Filter-in Bottle be laid on its side?
Yes, the cap seals, which is why it fits a fridge door.