Lemon in Cold-Brewed Green Tea: What Changes?

Something I Noticed While Testing a Recipe

Recently, while I was testing a new recipe, I came across something interesting, and I thought it might be worth sharing with tea lovers.

I was working on a Cold-Brewed Green Tea Lemonade recipe, trying to find a way to make it as easy and delicious as possible. I wondered, What if I brew the green tea and infuse the lemon all at once - in one bottle? It seemed like a straightforward and good idea. So I took a bottle, added some green tea leaves, a few slices of lemon, and filled it with water. Then I let it steep in the fridge for a few hours. When I tasted it...something felt a little wrong. It didn't have the delicate, refreshing taste I expected. The green tea flavor was muted, and it simply wasn't enjoyable.

My first thought was: Did I use the wrong tea leaves?
But then another possibility came to mind: Could the lemon have affected the green tea?

Comparing Two Brewing Methods

To test the idea, I did a simple experiment, using the tea leaves, Fukamushi Sencha, 深蒸し煎茶 (Deep-steamed green tea) and prepared two bottles.

Bottle A: Tea leaves + cold water

Bottle B: Tea leaves + cold water + half a lemon (thinly sliced)

I placed both bottles in the fridge to cold-brew for 3 hours. Here's what they looked like before and after cold-brewing.

Before Brewing

After 3 hours

After a gentle stir

Differences in Color and Taste

Bottle A: Green tea (left photo)

The color was a clear and vibrant green.
The taste was smooth and mellow, with a gentle sweetness and umami underneath the slight bitterness.

Bottle B : Green tea with lemon (right photo)

The color appeared dull, with a yellow-green tint.
The taste had a lemony sourness and some bitterness from the tea, but lacked the usual umami and sweetness.

The difference was clear — in both flavor and appearance.

What Does This Happen?

Green tea is best brewed in water that is slightly acidic to neutral(pH 6-7), which includes most tap water and bottled drinking water.

One key component of green tea is chlorophyll, which gives the tea its bright green color. However, in acidic conditions, chlorophyll breaks down and turns yellowish green. This explains why the tea in Bottle B lost its fresh green hue.

Also, acidic water (like lemon-infused water) may inhibit the extraction of amino acids like theanine, which is responsible for the tea's umami and sweetness. That could be why the lemon version tasted mostly sour and bitter.

Lemon is a beautiful, refreshing addition to tea, but if added during the brewing process, it can interfere with the delicate balance of flavors that high-quality Japanese green tea offers.

So, What is the Best Method?

Brew the green tea first, allowing its umami, sweetness, and vibrant color to fully develop. Then, add lemon after the tea is ready. This way, you preserve the delicate flavor profile of the green tea, while enjoying the fresh, citrusy lift that lemon adds.

(Photo: Adding lemon after brewing – left / Brewing with lemon from the start – right)