Hacker News Reader

Comment by taraparo | Hacker News Reader

the german tea expert Ernst Janssen recommends to also use boiling water to prepare green tea as most of the teas are contaminated with germs and other things. different green tea brands including organic tea brands were tested by the renowned German test.de magazine and they confirmed that, also most of organic teas are contaminated. and since this is nothing you can easily check at home, better use boiling water.

https://www.ernst-janssen.com/tee-almanach https://www.n-tv.de/ratgeber/Stiftung-Warentest-bewertet-gru...

View on HN

That seems paranoid considering that I have never heard anyone getting food poisoning from tea, no matter how it was brewed.

edit: Reading the linked article, it seems mostly concerned about contaminants and not germs. Intuitively thinking, I'd imagine higher temps would end up extracting more of those from leaves to the drink than lower temps?

Yeah it seems so dried out you wouldn't have too much to worry about.

As for boiling tea for sanitation, I took a wilderness first responder class and they taught us that you could bring water to a boil at any altitude a human can breath at (without holding it at a boil for 15 minutes as some claim) and it's considered sterilized. In Cusco, that would be around 191F/89C (humans can breathe quite a bit higher up than Cusco). Not a bad tea-brewing temp!

Also, I suggest trying kukicha. It's high in l-theanine and lower in caffeine. Tasty too.

> Yeah it seems so dried out you wouldn't have too much to worry about.

How about the people touching / sneezing on it in the packaging factory?

Not sure about most things transferred via touch/sneeze but I imagine lack of moisture would cause anything living to die fairly quickly.

Except aflatoxin.

If you source your green tea from a Japanese tea farm, this is really not a concern. Farm workers all wear gloves and masks, and the tea leaves are harvested directly from the tea bushes to a net via a machine.

Additionally, the tea plants are covered by cloth for up to a month before harvest, dramatically reducing the chances of bird droppings.

They are also steamed, rolled, and dried by mechanical devices which remove virtually all moisture.

Just a shout out to ikkyu tea, if you buy in bulk and get free shipping, it's a pretty good value for tea that you can trust.

I think it's a halflife/timing thing. Once it hits boiling, it's instance death for most microbials.

You can keep it a lot lower for longer but it's also potentially difficult to tell the temperature (easier to say, bubbles? It's hot enough)

Not really. Most microbes will be dead in a minute at about 70C. Milk pasteurization is done at 60C, after all. Most importantly, it'll kill salmonella.

Some hardy bugs and/or spores can survive regular boiling anyway, so you're not aiming for total sterilization.

It would be a really cool coincidence if the temperature at which water boils happened to be the magic number that killed most bacteria (unless it killed them because it boiled water they depend on to function or something), but I don't think that's the case - I think that boiling is something that's easy for humans to do and to perceive that also happens to be above the safe threshold and kill enough of the bacteria that harm us to make it a useful break point, even if the actual 212* isn't especially relevant.

Many bacteria have mechanisms for surviving dry periods, ex: https://link.springer.com/article/10.1007/s00294-019-01036-z

Unfortunately the bacteria that can survive drying-out are also the ones that survive boiling, so unless you're going to boil your tea in a pressure cooker it's not much help.

We'd be drinking gamma ray sanitized tea if that had really been a problem. Honestly it sounds like mercury scare in seafood and pourover rice cooking for arsenic reduction, just not-invented-here behavior.

> I'd imagine higher temps would end up extracting more of those from leaves to the drink than lower temps?

that is actually an interesting aspect.

The germ thing seems to go back to this 2005 press release by the BfR, which does indeed urge people to use boiling water to kill Salmonella particularly when preparing herbal tea. It doesn't cite any known cases or numbers: https://mobil.bfr.bund.de/de/presse/presseinformationen/2005...

Searching further, there were a couple of cases of Salmonella in infants in 2003 that were traced to fennel anise tea. The timing fits. I couldn't find anything more recent, but I didn't look very hard.

https://www.ernaehrungs-umschau.de/news/16-07-2003-salmonell...

Here's more data from government sources. They tested tea and herbal tea in 2008, and found traces of Salmonella or E.coli in 2-3% of prosecute products, and mold in 20%. Doesn't differentiate between herbal and real tea.

https://www.lgl.bayern.de/lebensmittel/warengruppen/wc_47_te...

I'm not worried. But then I usually use boiling water, or almost boiling water, which should be enough to kill micro organisms. And I'm sure I get more mold toxins from various other food sources without noticing it, cereals, nuts, processed foods etc. Tea is a dilution, after all.

You don’t need to boil salmonella to kill it:

https://ourdailybrine.com/wp-content/uploads/our-daily-brine...

You’ll have to work pretty hard to make a credible cup of tea with viable salmonella in it.

The more sensitive "proper" teas are well into the danger zones e.g. gyokuros tend to be brewed between 50C and 60C, and with brewing times under 3mn.

Never really heard of hard thermal limits for herbals though, in my experience they're more resilient and less caring, and you can long-boil most of them like you'd do a middling black tea.

By that standard, you should be really careful with matcha — you mix it will non-bacteria-killing water and then drink the whole thing!

I don’t know whether most pathogenic bacteria can survive prolonged dry storage conditions, though. And, if you’re worried, you could likely pasteurize your fancy tea by heating it, dry, to 60C or so for a while.

I’m not even remotely worried about tea-borne salmonella, just pointing out that per your link for higher-grade green teas the brewing temperature x brewing time is well below what’d be needed to destroy it.

While I usually boil tea water, I just remembered I sometimes do cold brew tea (overnight with straight tap water). No gastrointestinal discomfort yet.

One thing to keep in mind is that some teas (as in made from Camellia Sinensis leaves) are processed using a pan/ceramic firing or steaming step to stop the leaves from oxidizing. I'm not sure how hot it gets but there is a heating step that might affect the viability of some pathogens.

It makes sense that herbal teas might be more susceptible to pathogen contamination if they don't go through that.

Of course there's plenty of steps along the way to contaminate tea, and chemical contaminants are different. But boiling water isn't the only heating step for some teas.

Having said that, I generally just use boiling or near boiling water for all my tea. I've tried all sorts of combinations of temps with many many different varieties of tea and have decided that the tea variety, amount used per serving, and length of steeping make much more of a difference than the temperature. I also think I just like bold-flavored tea (I do like bitter flavors quite a bit, and have been known to seek them out even when I was too young to really be aware of a pattern with it).

Yes this doesn’t really make sense unless it would denature any toxins which doesn’t seem that likely and will do nothing for any pesticide or heavy metal contamination except possibly extract more.

A person I know had to get tested for toxins at work regularly and at some point showed really high arsenic levels. At which point they had to figure out what poisoned him. He worked in material science but no materials he handled would have given off arsenic to his body. After some investigating, they found out that the Pu'Erh tea he consumed was the culprit. They tested the tea in a lab and after he stopped drinking it, his levels became normal. So that might not kill.you but I guess having these toxins in you body cannot be good either.

Since then I try to only buy teas which are lab-tested. When I lived in Germany I bought my teas at sunday. Tbey tell you harvest, growing conditions and many more things and they also claim to lab test the tea badges.

I haven't found anything comparable in the US yet.

https://www.sunday.de/long-jing-shi-feng-tee/

Boiling isn't going to do anything about arsenic.

Sure, just wanted to add a data point about food poisoning yourself with tea.

Colloquially, "food poisoning" refers exclusively to (per Wikipedia) "Foodborne illness (also foodborne disease and food poisoning); any illness resulting from the spoilage of contaminated food by pathogenic bacteria, viruses, or parasites."

You might want to use water with high level of iron though. My grandfather used to use arsenic to brew cider because its local water had really high levels of iron.

Personally, I wouldn't count on it, see:

[1] Metal Attraction: An Ironclad Solution to Arsenic Contamination? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1257624/

Presumably you typo'd the elements here?

> After some investigating, they found out that the Pu'Erh tea he consumed was the culprit.

Oh wow. Wonder if they tested the same tea at the place he bought it from too.

Just in case... you know... the tea from there didn't have the arsenic in it. (!)

Of course, if he lived by himself that's unlikely to have been a problem. ;)

  > Intuitively thinking, I'd imagine higher temps would end up extracting more of those from
  > leaves to the drink than lower temps?

If we're discussing non-volatiles such as heavy metals, boiling acually concentrates them by removing some of the water. This is more of a concern with the water than with the tea, however if one is already bringing up the health aspects then obviosly neither can be ignored.

It’s not a matter of food poisoning, it’s a matter of do you really want to ingest contaminants. Regular consumption of contaminants such as pesticides, herbicides, and antibiotics (all present in the water supply especially at lower elevations) has an impact on long term health.

All foodstuffs are contaminated with germs, unless you go to extraordinary effort to prevent it (e.g. intense gamma radiation.) Unless there is some particular reason to care (you're a hospital feeding people who had their bone marrow nuked by cancer/chemo), then the correct solution is to stop caring. Who ever heard of people dropping dead because they brewed their tea with sub-boiling water? This isn't happening, it's not something you should worry about.

People mostly get by fine without boiling their salads but they do occasionally get e coli or something.

They occasionally get hepatitis or something and die.

https://en.wikipedia.org/wiki/Chi-Chi%27s

Oddly, the restaurants are gone, but there is salsa using the brand in some supermarkets still. I wouldn't buy it, even though it presumably is just someone else using the logo.

They still exist in my country! (Belgium)

That's widely understood, but I hope nobody is boiling their salads in response to that statistic. Maybe tomorrow I'll trip on my shoelace and crack my skull open on the sidewalk, but I'm not going to wear a helmet just in case. There is an endless supply of extremely low probability ways to die, but if you spend your time worrying about all that crap you'll ironically hasten your own demise by stressing yourself out. Round those small possibilities down to zero and stop worrying about it.

they even found salmonella in tea. to kill them one would need to heat the tea constantly above 70 degree Celsius over a period of ten minutes.

71°C for 1/2min to kill salmonella, instantly with 74.

10min is around 64°C.

Remember that the cup often cool down the water 10-15 degrees. So the water should not be under 90°C from the boiler to be safe.

Do they really use gamma, or just electron beams like in a TV tube?

Either.

Gamma rays are definitely used.

https://en.wikipedia.org/wiki/Food_irradiation

> "germs and other things"

This is faulty reasoning. The typical "almost boiling" temperature of 185F for 3 minutes will sterilize the tea just as well as boiling water would. There's absolutely no benefit in terms of safety. The only consideration would be flavor.

While I get the logic, it feels a lot like a "cook your salad to get rid of potential pathogens" strategy. Sure it's safer, but did you really want to boil your salad ?

There surely must be other ways to get probably safe food than boiling everything you drink.

If you are paranoid about salmonella in tea, 185F for 15 seconds is enough, and it won't ruin teas that taste better at lower temps.

Or you can top your drink up with very hot/boiling water after brewing

No need to boil. 80 or 90 degrees is enough to kill germs nearly instantly, 70 degrees takes a little longer.

Boiling doesn't even kill most things. I worked in a biolab for a while and used an autoclave to sterilize objects. It basically means we pressure cooked stuff at 130°C for 45min or so. And even that doesn't destroy some dangerous stuff like prions.

Without buying the test, looks my tea vendor (Tee Gschwender) once again was at the top, so I think I’m good ;)

This seems extremely paranoid.

I cold brew green (and black) tea and drink multiple cups a day.

This is an extremely German world view.

Dreck reinigt den Magen. Stellt Euch nicht so an, Ihr Weicheier!

Obligatory reference: "You are all diseased" by Geoerge Carlin: https://www.youtube.com/watch?v=X29lF43mUlo

Reply on news.ycombinator.com