Tea Mites ???
 

Hi,
Have 8-10 kgs of various forms of Pu'er (cake, brick, tuo) stored in a
reasonably tight hardwood cabinet (it's not air-tight). No holes or gaps in
the cabinetry. The tea is wrapped in it's original paper wrapping and
cartons.

Conditions inside are reasonably stable - but we do get the odd hot day here
in summer.

Anyway, I opened a 1990's cooked cake last night, one that had been opened
before, and I saw a minute bug, or mite. Very small - I'd say as an estimate
in size, say 0.1mm - really tiny. I checked the rest of the cake as best I
could and could not see any others.

Is this normal ? If not, is there anything I can do about it?. Our house
is kept reasonably clean and we have hardwood floors - so no carpet for
things to breed in.

Would appreciate any insight.
--
Cheers
Mal
Oz
http://maloz.bigblog.com.au/index.do

Tea Mites ???
 

Mal from Oz wrote:
> ... I opened a 1990's cooked cake last night, one that had been opened
> before, and I saw a minute bug, or mite. Very small - I'd say as an estimate
> in size, say 0.1mm - really tiny. I checked the rest of the cake as best I
> could and could not see any others.
>
> Is this normal ? If not, is there anything I can do about it?

I don't know about that specific insect, but am certainly concerned
about pests in my own stash.

Over the decades, I've had two infestations of flour weevils - little
bugs that get into even tightly closed jars. (Good article on such
critters at www.ag.ndsu.edu/pubs/yf/home/e300w.htm.)

They appeared almost simultaneously in rice, flour, pasta, everything
dry and farinaceous. The first time was long before the WWW and readily
available information on such things. Although an impoverished grad
student, I threw out everything, vacuumed the cupboards, and waited a
couple of weeks to re-stock. They came back. I realized that fumigation
was needed, but didn't want to use any remanent poisons in the kitchen.
In the end, I got some dry ice, threw a chunk into each cupboard, and
left the doors shut for a couple of days. It worked perfectly - CO2 is
quite lethal in high doses.

If I ever find creepy-crawlies in my Pu-erh, I'll probably do the same
thing. I'd stack all the boxes in a small closet, put in a few pounds of
dry ice, and tape the door shut for a week or two. Dry ice is readily
available in most urban areas, cheap, leaves no residue, and (IMO) is
very unlikely to induce any changes in the tea itself. On the other
hand, CO2 ruins coffee (why European bags have a vent), so I'd probably
test it first.

-DM

Tea Mites ???/2
 

> If I ever find creepy-crawlies in my Pu-erh, I'll probably do the same
> thing. I'd stack all the boxes in a small closet, put in a few pounds of
> dry ice, and tape the door shut for a week or two. Dry ice is readily
> available in most urban areas, cheap, leaves no residue, and (IMO) is
> very unlikely to induce any changes in the tea itself. On the other
> hand, CO2 ruins coffee (why European bags have a vent), so I'd probably
> test it first.

Oh, yeah - freezing would probably work pretty well too. Say, three days
below zero degrees F, though some bugs are pretty hardy. (USDA and such
organizations probably have info published on this.) I just have so much
tea now that I'd have to find a walk-in freezer or run a lot of batches
through a big cabinet freezer.

-DM

Tea Mites ???/2
 

While this reply has to be guesswork based on first principles rather
than experience I would not advise freeze sterilizing pu-erh to kill
insects or mites unless it was for immediate consumption (in which
case boiling water will suffice). Maturation of pu erh depends on a
healthy component of living organisms (good bacteria and fungi) which
freezing would kill. Dry tea is not generally attractive to mites;
chances are it's the fungi that the mites are eating. In standard tea
reducing the moisture would deter any alien insect growth, but again
pu erh needs some moisture for its maturation to continue. Carbon
dioxide for 72 hours is a standard insect kill method that would not
upset the fungi and bacteria too badly but requires the tea to be
infused with the gas in an hermeticly sealed vessel (taping up a
closet would not contain it or would need an excess of CO2 - which
also kills higher life).

CO2 does not ruin coffee - it's oxygen that stales it and quickly.
Freshly roasted coffee actually gives off carbon dioxide - the valves
are there to stop the pouches from exploding. Before valves the roast
coffee was left in the open to give off its gas (degas) for a week
before packing but this allowed a week for oxygen to wreak havoc with
the quality.

Nigel at Teacraft

On 29 Dec, Dogma wrote:
> > If I ever find creepy-crawlies in my Pu-erh, I'll probably do the same
> > thing. I'd stack all the boxes in a small closet, put in a few pounds of
> > dry ice, and tape the door shut for a week or two. Dry ice is readily
> > available in most urban areas, cheap, leaves no residue, and (IMO) is
> > very unlikely to induce any changes in the tea itself. On the other
> > hand, CO2 ruins coffee (why European bags have a vent), so I'd probably
> > test it first.

Tea Mites ???/2
 

Nigel wrote:
> While this reply has to be guesswork based on first principles rather
> than experience I would not advise freeze sterilizing pu-erh to kill
> insects or mites unless it was for immediate consumption (in which
> case boiling water will suffice). Maturation of pu erh depends on a
> healthy component of living organisms (good bacteria and fungi) which
> freezing would kill.

Interesting - while not any kind of microbiologist, it's my impression
from a couple of dozen food/drink projects (plus random reading) that
pathogenic bacteria and fungi are not usually killed by freezing.
Rather, their metabolism and reproduction are suspended for the
duration. Is there evidence that the living elements in Pu-erh that (are
alleged to) cause beneficial aging could be harmed by freezing?

> Carbon dioxide ... requires the tea to be
> infused with the gas in an hermeticly sealed vessel (taping up a
> closet would not contain it or would need an excess of CO2 - which
> also kills higher life).

Perhaps you could amplify here, Nigel. My empirical observation is that
this worked fine both times I tried it, without even bothering with tape
- I only mentioned that in case someone has a very loose-fitting closet
or cabinet door. The evaporating lumps of dry ice quickly fill whatever
space is needed, then continue to emit CO2 until they have sublimated
completely. Even then, I suspect that lethal concentration for bugs
isn't that much higher than the 10% or so that's fatal to larger
life-forms. Leaks and breezes in the average home would probably leave a
normal closet or cabinet at that level for a few days, once it was fully
"charged" with CO2.

> CO2 does not ruin coffee - it's oxygen that stales it and quickly.

I passed along the comment as cited by senior engineers (not scientists)
at what I think was then Europe's largest coffee company, during a 1990s
engagement to invent novel packaging and presentation designs. I didn't
believe it at the time, and am happy to correct the belief. Perhaps
their point was that absent a valve, the (two-way) leak required to
avoid bag explosion would allow in too much oxygen.


-DM

Tea Mites ???/2
 

On 29 Dec, 18:39, DogMa > wrote:
> Interesting - while not any kind of microbiologist, it's my impression
> from a couple of dozen food/drink projects (plus random reading) that
> pathogenic bacteria and fungi are not usually killed by freezing.
> Rather, their metabolism and reproduction are suspended for the
> duration. Is there evidence that the living elements in Pu-erh that (are
> alleged to) cause beneficial aging could be harmed by freezing?

I understand that the balance of kill versus suspended animation is
related to speed of freezing - a slow freeze being the most lethal -
quick freezing with intimate contact (liquid N) being non lethal. I
don't believe anyone has tested the effect of freezing on susbsequest
maturation of pu erh but would not want to risk mine to the the
uncontrolled and spatially variable cooling of a domestic freezer.

> > Carbon *dioxide ... requires the tea to be
> > infused with the gas in an hermeticly sealed vessel (taping up a
> > closet would not contain it or would need an excess of CO2 - which
> > also kills higher life).
>
> Perhaps you could amplify here, Nigel. My empirical observation is that
> this worked fine both times I tried it, without even bothering with tape
> - I only mentioned that in case someone has a very loose-fitting closet
> or cabinet door. The evaporating lumps of dry ice quickly fill whatever
> space is needed, then continue to emit CO2 until they have sublimated
> completely. Even then, I suspect that lethal concentration for bugs
> isn't that much higher than the 10% or so that's fatal to larger
> life-forms. Leaks and breezes in the average home would probably leave a
> normal closet or cabinet at that level for a few days, once it was fully
> "charged" with CO2.

Dunno. I have used it thus in what we in UK call a picnic box - an
insulated plastic box with a snap shut lid - this gave a virtually
100% CO2 atmosphere. English closets, at least, are pretty leaky
things. CO2 is heavier than air and will tend naturally to drain out
of a closet (like propane gas would, or diethyl ether). Our closets
would need more than the doors taping to hold in a heavy gas for
several days.
.
> I passed along the comment as cited by senior engineers (not scientists)
> at what I think was then Europe's largest coffee company ... Perhaps
> their point was that absent a valve, the (two-way) leak required to
> avoid bag explosion would allow in too much oxygen.

Yes, that was the problem with the then used pin hole valve, once the
positive CO2 pressure reduced then oxygen diffused in.

Nigel at Teacraft

Tea Mites ???
 

"DogMa" > wrote in message
...
>> In the end, I got some dry ice, threw a chunk into each cupboard, and
> left the doors shut for a couple of days. It worked perfectly - CO2 is
> quite lethal in high doses.
>

Thanks...
Ok, the CO2 seems to be a method to get rid of what I may have, but how does
one stop them getting into the tea in the first place ?

Hence the reason for asking if the presence of minute bugs, such as this
one, is normal. Obviously weevils are not good, but this one wasn't a
weevil - not like you get in flour anyway.

This is the first time I have seen any evidence of any such beasties in the
2 years the tea has been stored. The stash is only opened say once a month,
if that - my daily requirements are left out on the bench in clay caddies.
My point here is that the opportunity for critters to get in is small -
however the one I saw would easily be able to get in. I suppose also that
the bugs may have been in the tea when I bought it.

The one I saw could, I suppose, be the one and only..who knows..

...another thing to worry about !

Cheers
Mal
Oz

>

Tea Mites ???
 

> If I ever find creepy-crawlies in my Pu-erh, I'll probably do the same
> thing. I'd stack all the boxes in a small closet, put in a few pounds of
> dry ice, and tape the door shut for a week or two. Dry ice is readily
> available in most urban areas, cheap, leaves no residue, and (IMO) is
> very unlikely to induce any changes in the tea itself. On the other
> hand, CO2 ruins coffee (why European bags have a vent), so I'd probably
> test it first.
>
> -DM

Funny thing is that some people believe this to be good and keep such
bug-eaten pu as a prized part of their stash. Look up the bug poop
pu'er threads we've had here in the past.