Saving Teapots From Mold and Other Evils

[Richard Kilgore]

A True Tea Pot Confession

I swear I have never done this before. I always dump leaves and rinse a pot before returning any teapot to it's perch on a teapot shelf, lid off for a day. Always. Except a week or so ago. I had too many pots going at once and moved my smoothest brewing Japanese Banko back to it's perch with the leaves still inside with lid on, planning to do the dump-and-rinse before going to bed.

You guessed it, two days ago I picked it up again to use it and...greenish mold covered the leaves. After dumping and rinsing it definietly smelled musty-moldy. Afraid I would have to do something drastic like use a denture cleaner to strip it and then go through re-seasoning it. But I treated it with boiling water a few times and then added baking soda with boiling water and let it stand for a couple of hours.

The next day the moldy aroma was gone, but the first two sessions with the Banko left a faint baking soda slick in my mouth. Today, eureka! Back to normal for the most part. May have lost a very little seasoning in the process, but that's okay.

Anyone else have any tales of teapot neglect and redemption?

[Will]

I don't know if you can ever fully recover a stoneware / earthenware pot that's gotten moldy (if the leaves have mold, maybe, but if the pot has mold, probably not). Obviously, with porcelain, there's really no problem.

My method for putting yixing pots away is:

1) Remove leaves

2) Rinse any remaining leaves with fairly hot water (I use filtered or spring water, even for cleaning)

3) Rinse out the pot (including putting the lid on) with full boiling water. The hotter the better, because if the water is really hot, it will mostly evaporate quickly

4) Let the pot (sitting upright, not upside-down) and lid (facing up) dry for 2-3 days, depending on how humid it is where you live.

5) Put the pot away.

[Wholemeal Crank]

I've mostly blocked the distressing details from memory, but I did once leave a kyusu with leaves in it for quite a few days--I expected to come back the next day, and I'd only had one or two infusions of a very classy tea, but I didn't come back the next day, and when I did come back, I didn't remember that it had leaves in it. So.....it was some days before I realized the error--it's a pot I only use about once a week on average anyway.

It got bleached, if I recall correctly, copious rinsing, and a long airing out before I used it again.

[Will]

ps - If you don't want to use straight up bleach (dilute non chlorine or oxygen bleach solutions should be Ok), you can look for oxygen bleach based denture cleaner. Most store brand ones are mint flavored, but you can order unflavored 'sparkledent' powder (I think that's the name) online. You can clean some pretty funky pots with bleach of one sort or another, or just (very careful) alternating boiling and cool water treatments (don't shock the pot too quickly, and use a towel around it when you're boiling it).

[Wholemeal Crank]

I used about a 1:10 dilution of household bleach on that one sad stinky pot, and let it soak for about an hour. For less stinky concerns, I've been happy with denture cleaners, toothpaste, and elbow grease. I know the denture cleaners are powerful--they ate a nice stainless vacuum bottle--but hadn't considered them as potentially useful for sterilizating moldy stuff.

[andiesenji]

The best way to clean a teapot that has been infected with mold is with hydrogen peroxide.

Pour it in and leave it in the pot for at least an hour, rinse several times with hot water and follow with a vinegar rinse to neutralize any peroxide that may remain.

There are many molds that are resistant to bleach - it will remove the color of the mold, but will not kill the spores so the mold comes back and these spores can hide in microscopic crazing inside a teapot. Bleach will destroy bacteria and viruses and is excellent for removing stains from tea.

You can also use full strength distilled white vinegar and if the pot is microwave safe, heat it in the MW for 3-5 minutes, depending on the size of the teapot, then allow it to cool in the MW.

This has the advantage of also doing some cleanup of the MW interior - just wipe with a paper towel.

Don't open the door while the stuff is still hot, you will get a sinus-clearing jolt of vinegar steam.

You can also fill the pot with vinegar, place it in a larger vessel pour hot water around it and put it over low heat to keep the water hot but not boiling. An hour is optimum.

Denture tablets are fine for removing mineral deposits and will kill certain bacteria but will not kill all mold spores - some molds actually like some of the compounds that go into these tablets. The bubbles are produced by sodium hydrogen carbonate.

You can combine this with hydrogen peroxide to get a very effective cleaner but it will also remove the glaze from pottery, porcelain and etc. Not a good thing.

It's very effective in removing mineral deposits from stainless steel. I have tried it - outside - in a stiff breeze to carry away the fumes. I don't recommend it.

Oxygen bleach? Not so much effective on molds. I had a box in my garden shed - for scrubbing plant pots - it got damp and the top and end of the box had a fine crop of mold growing on and in it. We gingerly bagged and sealed it and put it in the hazardous waste bin at the local fire station.

Edited April 12, 2011 by andiesenji (log)

[Wholemeal Crank]

Denture tablets.....[are] very effective in removing mineral deposits from stainless steel. I have tried it - outside - in a stiff breeze to carry away the fumes. I don't recommend it.

I don't recommend it either for stainless steel. This is what it did to my thermos, when I just wanted to scrub the tannin deposits away--I had a theory, which I now know was wrong, that perhaps the buildup of tannins was the problem with some of my more delicate teas when put into the thermos:

That's steel etched by the tablets.

[andiesenji]

Denture tablets.....[are] very effective in removing mineral deposits from stainless steel. I have tried it - outside - in a stiff breeze to carry away the fumes. I don't recommend it.

I don't recommend it either for stainless steel. This is what it did to my thermos, when I just wanted to scrub the tannin deposits away--I had a theory, which I now know was wrong, that perhaps the buildup of tannins was the problem with some of my more delicate teas when put into the thermos:

That's steel etched by the tablets.

Oy! A disaster. I meant heavy SS stockpots that have developed crustal elements from boiling lots of water (say for pasta). My well water tastes wonderful but has a high percentage of minerals dissolved in it that precipitate out with boiling. I can boil straight vinegar to get it off but that also requires a session outside - with an induction burner - because of the strong fumes.

I just clean interiors of vacuum bottles with a bleach solution as I make sure never to leave anything inside them for a prolonged period and I store them upside down on a boot rack.

Edited April 12, 2011 by andiesenji (log)

[Will]

Oxygen bleach? Not so much effective on molds. I had a box in my garden shed - for scrubbing plant pots - it got damp and the top and end of the box had a fine crop of mold growing on and in it. We gingerly bagged and sealed it and put it in the hazardous waste bin at the local fire station.

The non-chlorine bleach that we use at home is essentially a strong hydrogen peroxide. Isn't hydrogen peroxide essentially an oxygen bleach?

[Richard Kilgore]

Thanks for all the good ideas. The tea-pot-in-distress is doing well, after brewing the ends of two packages of last season's shincha daily for a few days. I do keep some denture cleaner around for such an emergency, but did not have to use it. The mold apparently on top of the leaves and did not penetrate the clay.

[Richard Kilgore]

Did it again with an older Yixing with good clay that is no longer available> Yikes! Just discovered it tonight, and just beginning the treatments. I'll post on the results...on the positive results, he said.

[Wholemeal Crank]

So far I haven't had any clearly visible mold on the leaves or the pot, but I have let some leaves go more than one night in the refrigerator, forgotten, and they were definitely becoming unpleasant.

I wonder whether this sort of thing might be simply cured by baking the pot at a high temperature in the oven? Thinking now of how we sterilized things in the lab--most stuff was autoclaved, basically pressure cooked to 250 degrees. Some of the glassware that could take the heat was baked to 300+ degrees (can't remember now if it was 300 or 350), temperatures that break down even prions. Even a self-cleaning oven cycle ought not harm an unglazed clay pot, right? Though at that temp you're breaking down all the carbon compounds and probably losing all your seasoning too....

[Richard Kilgore]

Thanks, WC. As you suspect, I am trying to avoid losing the seasoning on this pot, which has a long history of being used for Oolongs by at least two previous Chinese owners. The last one is a teapot dealer who used it daily in his warehouse. The pot has very good clay, though less than aesthetically pleasing proportions. The clay, which was mined out, makes it a winner.

I have put it through several pots of boiling water, one with baking soda and am now doing another baking soda/boiling water treatment. If this does not work, I'll have to try something more radical. Wish me luck!

[Wholemeal Crank]

Luck!

I've only got a couple of pots that might have enough seasoning to affect the taste of tea brewed in them, but those are exactly the pots that sit with leaves in them overnight, because I tend to brew my green teas in gaiwans, and the oolongs and puerhs that might sit overnight....or be forgotten for longer....are the ones that I brew in unglazed pots. I know it's going to happen to me someday, so I'll keep following along with your efforts.

[Richard Kilgore]

Things are looking up. I am brewing a Dan Cong (it's preferred leaf) in it now and so far, so good. A little of the baking soda slickness, but otherwise okay. I'll have to do another two or three sessions to get the slick to go away.

This pot was so well seasoned when I got it that I poured hot water into the empty pot...and could taste the Oolong.

[Richard Kilgore]

Good news. Bad news. The musty smell is gone, at least for now. But the seasoning of many years and many pots of Fujian Oolongs is also gone. I need to brew a number of pots of Dan Cong to see what I really have here. Hope I don't have to truly take it back to day one in its tea brewing life.

[Wholemeal Crank]

Darn. Did you have to do more cleaning besides the baking soda, or is this loss from baking soda alone?

[Richard Kilgore]

Just several boilng water treatments and two or three of those with baking soda.

I am just now doing a session with the last bit of a Dan Cong from The Cultured Cup. The first infusion showed evidence of baking soda; the second one is okay. Before I brewed I poured hot water into the Yixing and then poured it out; the water looked golden like Dan Cong, but tasted mostly of baking soda. This is my only pot that has seen such long term use that when I first got it, Oolong water resulted from simply pouring in hot water. So just brewing a lot of Dan Cong may do it.