Why you need to cold brew your tea

Growing up in Texas, tea meant heavily sweetened iced tea which was frequently more just like sweet colored water. I struggled for years to make good, iced tea. My mother, the undisputed queen of sweet tea, used Lipton or Luzianne tea bags and steeped it with at least a full cup of sugar. I thought just using good-quality loose leaf tea would make the difference, but I was wrong. Sure, it was an improvement, but often it was cloudy or too strong (it must stand up to all that ice, right?). I also tried sun tea and came up with things that were fine but not great. Even if I got it exactly right, the flavor would go stale and not hold up over time.

It was not until attending the World Tea Expo in 2018 that I tried Glenburn Moonshine (A delicious white tea from Darjeeling) as a cold brew. The floral flavors and nuances were amazing. I kept going back for more (the fact that it was 116 degrees in Las Vegas may have factored into this decision).

I began to experiment with brewing tea in this way and it has opened a new world for me. I had previously not been a fan of many Japanese Green teas. Bob loves them and can brew them beautifully. I found them to be consistently persnickety. Frequently I would ruin expensive good tea. Then I tried organic Gyokuro as a cold brew and it was like the sky opened and the angels sang. The sweet umami flavor all the nuances came alive with none of the bitterness that I so often associated with Japanese Green Teas.

A little chemistry lesson

So, I wondered why is brewing tea hot and chilling it so different from cold brewing?  Turns out it has a lot to do with chemistry. I am not a food scientist, but I do read a lot of good books see “Tea: A Nerds Eye View” by Virginia Utermohlen Lovelace MD or “Infused: Adventures in Tea” by Henrietta Lovell.

Catechins, sometimes called tannins, are not easily extracted at cool temperatures. These catechins are what give a tea its astringency and bitterness. One great advantage of cold brewing tea is that you do not get the bitterness that you can with brewing with boiling or hot water. While some components of tea are not easily extracted in cold water, water soluble amino acids such as theanine are easily extracted. These amino acids give some teas a sweetness and umami quality.

Other compounds that produce undesirable flavors in tea that are not extracted in the cold brew process are dimethyl sulfide and indole. Dimethyl sulfide which is prominent in green teas can produce that slightly fishy odor. This probably explains why I enjoy the Japanese greens more as a cold brew. Indole in lower concentrations is perceived as slightly floral but larger concentrations as somewhat gamey.

As for chilling hot brewed tea to create iced tea, Henrietta Lovell relays a story in her book Infused about developing an iced tea for Momofuko. She states that the cell walls of the tea are ruptured by the hot water allowing the tea to oxidize more rapidly. The basically causes the tea to become stale over a period of minutes. She preformed a taste test with Sommeliers that tasted the same tea brewed the same way that had sat for 15, 30, 45, 60-minute intervals. The consensus was that the first fresh brew was significantly better.

So, if you have not figured it out already, I only cold brew my iced tea now. Since it does not have the bitterness, I don’t find that sweetener is necessary (I do not generally sweeten my teas as I prefer my sweets on the side in the form of cookies and cakes). It could not be easier and there is no special equipment needed to brew it, although you can find great cold brewing vessels from HARIO  (the Japanese word for such a vessel is 水出し - mizudashi) or in your local housewares store.