Oil Slick

Maurice,

Occasionally "hard" water (water with a high mineral content) will form a "skin" on the surface of brewed tea. I've read that compounds in tea will bind with the minerals, forming this skin. Dogma, if he's lurking, will probably be able to tell you more about the chemistry.

I don't know if this is what you're seeing or not, but where I live (eastern PA) this happens a lot with tap water.

Regards, Dean

plants like animals are made with lipids (fat).

at least the eukaryote cell membrane like in animals is made up of a phospholipid bilayer (=cholesterol and other goodies)

so... the oil slick is fat that comes out from the tea leaf.

its good ;) its all natural ;) unless the plant was sprayed with some chemical that now gets to float in our teas (alongside the plant's own extract).

As far as I know, it's tea oil or rather camellia oil. All tea has some oil properties, similar to that of coffee. A lot of the anioxidants that are in your tea are contained in the tea oil. It's nothing to worry about, but sometimes can be a sign that you're using too hot of water to steep your tea.

Desirea The Steeping Pot

Well I am in africa at the moment and the water here has a lot of chemical content in which really clouds up the flavor of the tea, so I went out and got 4 cases of evian water and the flavour of the tea is incredible however I still see this strange film appear on the surface and the teas that have this are not really fresh tatsting either so I thought it could be some conatmination in them.!

It's a plant. Not everything in it is water-soluble. Some of the things that create the great scent, in fact, are in that oil slick.

--scott

Long-jin (Lung-ching), from Hangzhou in mainland China, is fried in a wok using a either a small amount of tea-seed oil or bee's wax. I have seen a very slight slick on top of cups of it.

(This also relates to the issue of whether a tea is kosher.)

Best,

Rick.

Maurice!

Hey mate!

Tea contains very small quantity of volatile oils that contributes greatly to the aroma and favours.

But I doubt if this is what you are seeing ...

If the tea is panfried, or roasted, whichever way you call it, they might have used some oil in the process.

I see it in my finest longjing tea, but I am not sure if it is as much as you described.

Julian

Rick,

I'm curious about the kosher aspects of tea. Beeswax is kosher (see

and I'm assuming tea-seed oil is also, as it is derived from a plant. Aside from frying tea in lard ;-),what would make a tea without added flavorings (which may be from a non-kosher source) kosher or not?

Thanks,

Alan

Wissotsky, has the OU (U inside Circle) Orthodox Union logo, is a brand from Israel you buy in the US. Stash teas are certified kosher. You find links like this which talk about kosher teas:

Jim

PS > Rick,

Leached tannins on the water surface look like an oil slick. I use the term sheen. It's what gives the patina color to a pot. Sometimes you see it sometimes you don't.

Jim

magicleaf wrote:

Hi Allen

Shabot shalom ! Regarding kosher aspect of tea I can only say that I have been to china and observed the process of tea beeing made which undergoes several processong stages to reach the end product. For any thing to offficually be Kosher a rabi must approve the premisies and process and any additives applied and then only is it stamped kosher. In many cases the bethdin stamp of approval requires the rabi to be present. one can only be comfortable with how strict one observes the rules. In the case of tea generally it is a natural agricultural product and I would assume that it would be a very difficult and inconvenient task for a rabi to execute.

Maurice

I thought we established that tea doesn't have tannins.

"The term "tannins" has been used by many to describe certain tea constituents. In industrial and botanic literatures, tannins are characterized as plant materials that give a blue color with ferric salts and produce leather from hides. Thus, tannins are a group of chemicals usually with large molecular weights and diverse structures. Monomeric flavanols, the major components in green tea, are precursors of condensed tannins. It would be more appropriate to use the term "tea polyphenols" or "tea flavanols" because they are quite distinct from commercial tannins and tannic acid."

That said, I don't think the sheen is from oil used in the roasting process, and IIRC, there is a name for this phenomenon (at least in Chinese), and that the sheen is (if anything) a desirable thing.

w

If you look at the dictionary definition for tannin then there is nothing wrong with the term 'leached tannin'. Tea will stain your teeth and can be used as a wood dye which is more or less the historical reference to the tannin use. I think it is a tannin still used with cotton today. Don't let any dry on a granite countertop. It is not a trivial tannin to remove. If you're talking about biochemistry that is something else. I didn't know there was a Chinese character for the sheen characterization but all things tea in China has a name. Does anybody know what it is or at least the pinyin.

Jim

Will Yardley wrote:

[Jim] [Alan]

Hey guys,

This kosher thing came up earlier. At that time I contacted the people at Generation Tea who claimed to have certified kosher teas. They told me this: Tea is inherently kosher, being neither milk nor meat, but people -- presumably Jewish people in this case -- like to see the " certification"so they certify it. It's not necessary, it means little or nothing. That's what the Generation folk told me.

Michael

I find that interesting coment from generation Tea. quoted (Jewish people in this case -- like to see the " certification"so they certify it.) This certification carries a hefty price tag , therefore find it hard to believe that kosher people want to pay more money just for a stamp that means "little or nothing."

Maurice

Organic or Natural is still not Kosher for people of the Jewish faith. I saw one website mention what you said. They would have to pay for a Rabbi to travel to China, etc which made it too expensive. I'm sure there would be ongoing costs for certification. So what you see in the Jewish stores are products from Israel. Probably due more to logistics than a source of 'healthy' food.

Jim

magicleaf wrote:

That makes more logical sense!

Back to the tannins I was under the impression that the tanin carries the bitterness that comes out of the leaf after steeping it for too long, and that tanninn is common chemical found in plants more in some than others and that this bitter taste in some plants is very pronounced to fend off predators that eat the plant and would be put off by its bitter taste. Maurice

It depends also on how it is killed. You have to drain all of the blood out of the tea bushes under supervision of a rabbi. In addition there are many popular flavoured teas, such as lobster tea, which are impossible to certify as kosher. And even conventional meat teas cannot be served with milk.

--scott

Maurice, in fairness to Generation Tea, it was my paraphrase of an e-mail correspondence from GT, *not* a quote. Perhaps it was more a mention, a self-proclaimed declaration, than a certification. Nonetheless, they did state that tea is intrinsicly kosher *unless they use porkchops to mix it*. (italics and italicised text mine)