White Labs Yeast, may have insects in it.

[Grossy]

I do 20 gallon batches, and I made a 1 gallon starter the night before my brew day.

Starter process:

Since I do not have a stir plate large enough for a 1 gallon starter, my process is this:

The night before.
Boil one gallon of wort in a pot with a glass lid, this sanitizes everything.
Cool the wort to 70 degrees in the sanitized pot.
Pitch the yeast. Stir as much as possible.
This has worked well many times.
​

The morning of the brew day there were about 20 flies in the starter, little gnats.

My assumption was that somehow these insects worked there way under the lid and got into the starter. I had no expectation that this could have come from White Labs.

During the mash I ran down to the brew store, purchased 3 more packets of White Labs WLP001, MFG Date: SEP 03 2017.
I looked carefully through the plastic of the starters, I did not see any flies in the packet, but there were black specs. The plastic packet is translucent, not quite clear. The black specs could have been part of the manufacturing process.

I remade a starter, and sealed the top of the pot with Saran Wrap. I know the seal was good, because I had to continuously let off the CO2 pressure that would balloon up the wrap.

About an hour later, there were 5 flies in the starter. I removed the flies . I also but some of the wort from the starter in a cup next to the starter to see if I could attract any of these flies. None did. A full day later and no flies have gone into the open cup of wort. And there are no flies in the house.

If there are no flies in the house, starter was sealed, and no flies have been attracted to the open wort, where did the flies come from?

I hope the IPA comes out, $170 of ingredients and a day of work. Ill let you know in a month.

Anyone of here of this before?

 

[Grossy]

Picture of the flies:

 

[fragglerock]

Very interesting. Never heard of this before and I use WL almost exclusively. My apartment has no AC so I'm always keeping windows open and I can say that flies can get anywhere, including places you'd never think possible. Maybe try emailing WL? If it is a problem with the yeast, I'm sure they would want to know.

 

[Grossy]

I still dont know, and I really do find it unlikely that WL is responsible.

But as of now, the wort in the cup has not attracted any flies. I live in Arizona, it is 95 degrees and the house is sealed up with the AC on. The AC has been on for the last 6 months.

It cant be just the 5 packs of yeast I bought, other people would have the same problem.
Before I go and complain to WL, I think we will hear from other people as well.

 

[GilSwillBasementBrews]

I primarily use white labs yeast and have never had any issues with bugs in my yeast packs.

 

[IslandLizard]

Many of those glass pot lids have a vent hole, some have it under the knob. Can larvae come in through that or hide under there?

Are you sure they're not in your house?
I don't think these flies can survive the refrigerated temps yeast is commonly stored at for weeks to months.

 

[tvissoc]

I get fruit flies in my airlocks all the time. At least here in OH, its the season for those little dudes. They can squeeze through surprisingly small places. Like through the holes in the the lid of a 3 piece airlock.

 

[Dog House Brew]

This is why I cover my 5l flask with a coffee filter and rubber band it. I had this happen to me a few times. They are in your home somewhere. Mine came off of onions both times. I never pitched it afraid of infection. I now keep dry verities on hand because of those little f***ers.

 

[Smellyglove]

This is why I cover my 5l flask with a coffee filter and rubber band it. I had this happen to me a few times. They are in your home somewhere. Mine came off of onions both times. I never pitched it afraid of infection. I now keep dry verities on hand because of those little f***ers.

Genious idea. I've never thought about that before. I've thought about sticking some cotton down the neck, but with a potential blow-out that would be pretty sucky. Thanks for sharing!

Until now I've use alufoil and sort of gently covered the mouth of the flask, to get gas-exchange, but I've gotten fruit-flies into the flask also.

 

[mongoose33]

Would cheesecloth be a reasonable solution? Still get some air exchange, but keep the FF out?

 

[MaxStout]

Get a foam stopper from the brew store. Lets air in, CO2 out, but keeps out the bugs.

 

[Dog House Brew]

I use the filter Air goes in and out. I do still put loose foil on top. I think they would make it through cheese cloth. They have gotten through cheap paper towels I first used. No issues since moving to the coffee filter.

 

[DrunkenCanuck]

I get fruit flies in my airlocks all the time. At least here in OH, its the season for those little dudes. They can squeeze through surprisingly small places. Like through the holes in the the lid of a 3 piece airlock.

Huh, I have never had that and I get fruit flies a fair bit. I try to ensure that I have emptied out my garbage cans a day or two prior to a brew day, that way they aren't hovering around and likely to get into the pot.

 

[Grossy]

Like I said, I do not suspect White Labs... but.

There is no vent in the glass lid, the second batch was sealed air tight with saran wrap, and the open cup with wort in it did not attract any flies.

You would think that the open cup would have had some flies in it, is still does not 24 hours later.

A mystery.

 

[IslandLizard]

Here is another remote possibility. Maybe the outer sleeve of the WL packs harbors some larvae, for whatever reason. I always take it off so the inner plastic pouch can be sanitized, cut and emptied properly.

 

[NeoBrew]

Am I correct in remembering that the new White Labs packaging is actually what is used to cultivate the yeast? My understanding is that the yeast never sees open air as it is manufactured. Does anybody know more about this?

 

[IslandLizard]

Am I correct in remembering that the new White Labs packaging is actually what is used to cultivate the yeast? My understanding is that the yeast never sees open air as it is manufactured. Does anybody know more about this?

That's correct, the (inner) sleeves are made from the flexcell yeast propagator itself. It's a cleanroom process. White Labs' site has a very informative article on their patented pure pitch process.

I would sincerely doubt the flies/larvae come from them. But there is a distribution chain and final retailers where things are not so tightly controlled. Then there's the homebrewer making starters in a covered pot...

Aside from the large opening of a pot, yeast needs O2 to propagate and build healthy daughter cells. Without some form of constant aeration/oxygenation and agitation, the OP is merely making a small beer, which has some yeast growth, but far from optimal.

Aside from 2 liter wide neck flasks, I use 64 oz glass pickle jars to make starters in using a stir plate or orbital shaker. I too boil starter wort in a large SS pot, using my induction plate, then chill the well covered pot in the sink or a tub with cold water, which I replace once or twice. I add a couple ice packs when I'm in a hurry.

I do turn the AC/heat pump off when working with yeast, if I remember to do so before I hear it cycling on.

I've had 2 starter infections over the years, making 100+ starters. Both were my error.

 

[Northern_Brewer]

Normal lab practice is to use low-density foam rubber plugs in the mouth of Ehrlenmeyers, with some foil over the end to keep it dry during autoclaving.

 

[IslandLizard]

Normal lab practice is to use low-density foam rubber plugs in the mouth of Ehrlenmeyers, with some foil over the end to keep it dry during autoclaving.

I still use (heavy duty) aluminum foil "tents" over the opening. Actually a double layer of them, as I've found a few pinholes appearing after a day or so, likely due to Starsan attack. With the double layer, one covers the other.

Can those foam stoppers be sanitized/sterilized? Reused?

I never sterilize my yeast flasks and jars in an autoclave/pressure canner, simply because I don't have one. Just clean them thoroughly, PBW and a brush, then use Starsan. Once in awhile they go in a 250F oven for a couple hours.

 

[Dog House Brew]

The foam stoppers can be reused. I do not have any, but I’ve read that they can. I would like to have a few. They are always out of stock at the LHBS.

 

[IslandLizard]

The foam stoppers can be reused. I do not have any, but I’ve read that they can. I would like to have a few. They are always out of stock at the LHBS.

I saw the foam stoppers at my LHBS, but there was a hefty sticker shock attached, IIRC. I try to avoid overpaying for dime-valued items, especially if there's a viable alternative. I have had 0 issues with the foil tent, and have an inkling the foil tent exchanges gas better, being more "open." Don't they use foam covers over microphones to keep wind noise down?

 

[Northern_Brewer]

They can be autoclaved repeatedly, although eventually they get a bit cooked and lose their "spring" after a year or two - but they're cheap enough. You can get sheets of foam rubber, I imagine you can just cut your own.

No idea about how they'd react to chemical sterilisation - I'd imagine they might not react well to some strong chemicals, and also you'd be soaking them in solution so they'd take ages to dry out. I'd imagine a better way would be to microwave them with a little water, use steam to penetrate the pores without saturating them.

But all I know for certain is autoclaving/pressure-cooking them.

 

[MaxStout]

I saw the foam stoppers at my LHBS, but there was a hefty sticker shock attached, IIRC. I try to avoid overpaying for dime-valued items, especially if there's a viable alternative. I have had 0 issues with the foil tent, and have an inkling the foil tent exchanges gas better, being more "open." Don't they use foam covers over microphones to keep wind noise down?

That's where the LHBS makes a good chunk of its profit--from markup on all the little "add on" items.

My local store charges about a buck for them, so I picked up a few. I boil them in water to sterilize right before use.

Yes, they use foam for mic windscreens. Transparent to sound, but deflects air to prevent wind noise, popping P's, etc. Not sure if that kind of foam can withstand the heat from sterilization, though.

 

[IslandLizard]

That's where the LHBS makes a good chunk of its profit--from markup on all the little "add on" items.

My local store charges about a buck for them, so I picked up a few. I boil them in water to sterilize right before use.

Yes, they use foam for mic windscreens. Transparent to sound, but deflects air to prevent wind noise, popping P's, etc. Not sure if that kind of foam can withstand the heat from sterilization, though.

I think they were much more premium priced or I would have gotten some.

The mic windscreen was my point. Not saying it's the same foam, but if foam prevents air to penetrate, how does it breathe as a stopper/plug? It's fairly thick, like 1.5" high. That's a lot of foam to penetrate, in both directions, and air it can hold onto. We know there's some outgassing because of some side-fermentation, but that's outward. The inward flow of fresh air is more what we need.

IOW, how transparent are those foam plugs to gas exchange?

 

[MaxStout]

I think they were much more premium priced or I would have gotten some.

The mic windscreen was my point. Not saying it's the same foam, but if foam prevents air to penetrate, how does it breathe as a stopper/plug? It's fairly thick, like 1.5" high. That's a lot of foam to penetrate, in both directions, and air it can hold onto. We know there's some outgassing because of some side-fermentation, but that's outward. The inward flow of fresh air is more what we need.

IOW, how transparent are those foam plugs to gas exchange?

Mic windscreens don't prevent air from passing, they only deflect blasts of air from the mouth of a speaker or vocalist to minimize mic "popping." The windscreen provides a soft barrier that is acoustically transparent. By appearance, the foam appears the same in structure to that of the foam stoppers for flasks. But I don't know if the mic windscreen foam is made from the same polymer and can withstand the heat of boiling or autoclaving.

The foam stoppers do let air and CO2 pass, but they trap microbes and particulates. And you can boil or autoclave them without deterioration. After time, they do start to turn yellow and smell kind of nasty, so I toss it out after a few starters. At 70 cents a pop at my LHBS, it's not a bad expense. Funny that NB get $2.50 for them.

 

[triethylborane]

I have had 0 issues with the foil tent, and have an inkling the foil tent exchanges gas better, being more "open."

A foil tent will have "openings" that would be massive for CO2 and O2 molecules, but far too small for microbes to enter. The size difference between a microbe and a CO2/O2 molecule is several orders of magnitude.

Ive had this discussion here with individuals that think the foil doesn't allow for gas exchange because either the foil is "too tight" for molecules or the CO2 from the yeast metabolism won't allow O2 to enter the erlenmeyer flask as it is "pushing" it out . . .

Regardless, lab practice is a foam stopper or a foil hat. There are erlenmeyer flask caps that have built in filters, but for home brewing purposes, its just not necessary.

 

[triethylborane]

IOW, how transparent are those foam plugs to gas exchange?

Intuitively, you know the answer. When you pull a foam stopper from the erlenmeyer flask, is it like opening a can of carbonated soft drink? Same goes for the foil hat, does it bulge from the CO2 . . .

 

[MaxStout]

Intuitively, you know the answer. When you pull a foam stopper from the erlenmeyer flask, is it like opening a can of carbonated soft drink? Same goes for the foil hat, does it bulge from the CO2 . . .

Those tiny holes in the foam will trap microbes, but for gas molecules, it's like BBs going down a hallway. The gas diffusion law means that air will find its way through.

 

[IslandLizard]

Intuitively, you know the answer. When you pull a foam stopper from the erlenmeyer flask, is it like opening a can of carbonated soft drink? Same goes for the foil hat, does it bulge from the CO2 . . .

Hah!
Intuitively I don't think the gas exchange through a foam stopper is as good as it is with a foil hat. Those openings around the hat are indeed huge (on molecular scale) and offer NO resistance. Turbulence around that top opening allows for gas exchange. I see the foam as a more restrictive barrier, especially at 1.5" thickness, with far less turbulence at the gas exchange site.

Would be a nice exbeeriment to do 2 starters side by side, one with foam, the other with foil.

 

[triethylborane]

Those tiny holes in the foam will trap microbes, but for gas molecules, it's like BBs going down a hallway. The gas diffusion law means that air will find its way through.

Yes, I think it was more like a human on the surface of the moon IIRC the calculation correctly.

 

[Dog House Brew]

I use the coffee filter because of the bugs. I get them routinely in the House. Foil only lets them in. I would think the foam stoppers work great. After losing a few starters, gotta have an addition to the foil. If I hadn’t had the trouble I’d never use anything but the foil.

 

[MaxStout]

Hah!
Intuitively I don't think the gas exchange through a foam stopper is as good as it is with a foil hat. Those openings around the hat are indeed huge (on molecular scale) and offer NO resistance. Turbulence around that top opening allows for gas exchange. I see the foam as a more restrictive barrier, especially at 1.5" thickness, with far less turbulence at the gas exchange site.

Would be a nice exbeeriment to do 2 starters side by side, one with foam, the other with foil.

Or have two chambers, one containing air, the other containing a different gas. No pressure differential between the two. Connect the two chambers via a tube that is plugged with a foam stopper. Wait 24 hours and analyze the gas in each. Repeat the experiment using foil over the rim of a tube.

 

[Grossy]

Ok the results are in.

This might be the best beer I have ever made.

Conclusions:

1. The infection that I feared never happened.
2. I really doubt that the flies came from the yeast, or the DME. they had to have gotten in somehow. I will re-evaluate my process.
   
3. And finally... flies make great beer, I highly recommend them.