To Rinse Or Not To Rinse? Another Look at Rinsing Tea Leaves

One area of frequent contention in the tea world- and there are numerous such topics- is whether or not tea should be ‘rinsed’.

For the uninitiated, rinsing means adding hot water and discarding the brew nearly immediately without consuming that brew.

The purpose of rinsing is two-fold

i)   Getting rid of dust, microbes and other impurities

ii)   Giving the tea leaves a ‘warm-up’, getting it to unfurl and making subsequent brews more flavorful

The argument against rinsing is that the nutrients of the tea are lost.

My personal belief is outlined in this article which summarily I think that in general green, white and yellow teas should not be rinsed while most black, oolong and dark (post-fermented) teas should be.

Hairy Furry Details

Recently I read a research report that reinforces this stance.

It examines the nutritional content of the ‘downy fur’ found on Silver Needles against the content in the leaves itself.

Here is an extract of the table

Mg/g Downy Fur Leaf Fur as % of total (Downy fur/downy fur +leaf)

EGC 3.15 10.81 23%

EGCG 61.26 75.26 45%

Total Catechins 94.14 123.71 43%

Caffeine 36.93 48.45 43%

Asp & Glu 6.22 4.51 58%

Theanine 17.56 11.88 60%

(Source: 白茶-科学，技术与市场 editor叶乃兴 published by中国农业出版社 pg 40 & 41)

The photo shows the downy fur of the Silver Needles, giving it an almost whitish appearance.

I measured 4 g of Silver Needles and used 2 identical gaiwans (~100ml).

The gaiwan on the right shows a Silver Needle which has been rinsed- decanted within 10 seconds- and the second shows one that is not.

Without the aid of a lab and trained scientific personnel, I eyeballed the 2 gaiwans. As expected, there were some downy fur that was lost in the ‘rinsing’, the cup on the right had a ‘guestimated’ amount of 40-60% less downy fur.

Unfortunately the contrast in the quantity of fur doesn’t show up as well as photo shown below as I would have hoped.

Now this figure is just a guess, I can’t pretend to be brilliant at counting minute pieces of white fur floating around but it does lend credence to the loss-of-nutrients argument.

Let us look at the table again

58% of the total Asp & Glu (glutamic acid) content is found in the downy fur. Theanine is even more significant at 60%.

Let us assume that 50% of the downy fur was lost in the rinse. That would account for a 30% drop in theanine content.

For Fur’s Sake

So does that mean that across the board we cease rinsing?

Well, based on this argument alone, we still should not do so.

Downy fur is not prevalent in all tea leaves. It is most dense in the buds- such as the Silver Needles- followed by partially grown and young leaves. As the leaves mature, it becomes shorter and eventually falls off. By the 4^th leaf, essentially there is no fur at all. (source 中国茶叶大词典by 陈宗懋)

Without complicating matters by discussing cultivar and elevation, let us re-look at the general picking requirements for each category of tea (if you have read this before, please bear with me, it is a useful concept that has numerous applications:

Category of Tea Picking Requirements (General)

Green 1 bud to 1 or 2 leaves

White 1 bud to 1 or 2 leaves

Yellow 1 bud to 1 or 2 leaves

Oolong 2-4 leaves

Black 1 bud to 2 leaves

Dark aka Post-Fermented 4-5 leaves

Hence green, white and yellow tea tends to use younger leaves which all else being equal has higher downy fur.

For oolong and Puer, you would expect the downy fur content to be pretty low, if at all present. As such, the loss in nutrients due to the loss in downy fur is negligible.

This conclusion is not in conflict with the superior taste that comes from a ‘rinsed’ brew against an un-rinsed one if you are gongfu brewing oolong or Puer especially.

What do you know? You don’t have to compromise taste for ‘health reasons’ in the tea world.

Ain’t tea grand?

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