Steeping green tea leaves - how many times can I steep them, and do they lose flavanoids over steeps?

Question

I order my green tea leaves in small vacuum sealed baggies from China. They are crumbled up, but expand out once they become saturated. I typically use maybe half a teaspoon of these dried tea leaves, and I usually steep them around 5-7 times. Each time I steep my leaves (I use a personal french press for this) and I pour the tea into my cup, the tea is colored (obviously). The color of the tea never seems to fade between steeps.

2 questions:

1. When I pour my tea, if it's colored still, does that mean I am still getting flavanoids from the leaves?
2. How many times can I steep my tea before it starts to lose the flavanoids?

Answer 1

Nutrition itself is off-topic. However, keep in mind the following:

There are many compounds in tea leaves and some dissolve early, and some a little later. At some point (around 5-10 minutes of steeping at ~95°C), you will lose majority of the 'good stuff' and continue picking up less desirable compounds.

You will notice that while colour might persist, the taste will be come less and less desirable. In some cultures re-using tea leaves is considered a faux-pas because of this.

If you find your tea to be too strong after steeping, the best thing is to reduce the amount of leaves for the next time; as opposed to steeping them multiple times.

Answer 2

Tea is made from leaves of the Camellia Sinensis plant, which can grow in many parts of the world

25% of the leaf dry mater is the Catechin Polyphenols. This is present in all main tea types (white, green, and black). They also contain other Polyphenols like Theaflavins, Tannins, and some Flavonoids

Catechin is the main Flavanol (not a Flavonols) present when tea is steeped in hot water

The combined Polyphenols in a 200 ml cup of tea would be from 50 to 500 mg

The Flavanols and Flavonoids give tea the astringency, bitterness, and colour we associate with traditional tea, and also the distinctive after-taste

While all these chemicals are highly water soluble chemicals, they dissolve at different rates, and cannot be entirely dissolved out on the leaf cellular structure with heat and damage to the leaf structure

Repeated steeping with continue to work, though the flavour will change with each steeping as different Polyphenols dissolve out at different rates

Some people rinse the tea leaves in warm water for minute of two, and discard this water. While you will loose large amounts of Caffeine, you do also remove some Tannins that can be quite bitter and be part of the metallic after-taste

The finer ground or crushed the tea leaf, the more Polyphenols you can extract from them, and the more steepings you will be able to achieve

Increasing the heat of each steeping will also help in releasing more Polyphenols