Wild yeast infections (probably)

[chrisr]

Perhaps you good folk could give me some advice on how to deal with a problem I keep getting. I’m suffering recurring problems with wild yeast infection. I think.

At least, that’s my diagnosis; the beers lose almost all sweetness, end up too bitter and are faintly tart/tannic. There are no ‘off’ aromas. Typically, the beers will taste fine a week into fermenting, but by 10-14 days you can tell something isn’t right. So it seems whatever is happening starts after the activity of the desired yeast has started to slow. If anyone has any other theories as to the cause, I’d be glad to hear them.

If it is wild yeast, then obviously it’s entering cold-side. This is what I’ve tried to combat it:
1/ A different yeast. I prefer to use yeast I got from a brewery, but I’ve tried setting that aside and using dried yeasts. Starting with a fresh packet might give one or two good brews (I reuse the yeast) and then the impostor is back. I don’t really want to use a fresh packet of dried every time, as I would prefer to use the brewery yeast.
2/ Following yeast pitching, activity seems to get underway fairly quickly, and usually the airlock has started bubbling by the evening of the day I brewed.
3/ The plate chiller is cleaned out with hot sodium percarbonate or a VWP-type cleaner after every use, and stored filled with Starsan. I did try cleaning with caustic soda once (but it’s horrible stuff to use).
4/ I’ve replaced the pipe from the chiller to the barrel, and use it only for that purpose. I soak that in VWP-type cleaner after every use.
5/ The oxygenating ‘stone’ is boiled before and after every use.
6/ I use oxygen, not air.
7/ If I use yeast nutrient, I add it to the boiler
8/ The fermenting bucket (plastic) is washed after every use, and if not stored with VWP-type cleaner in it, it gets soaked in it before use. And I spray it with Starsan before use.
9/ I’ve tried acid cleaning the fermenting bucket. And caustic soda.
10/ I replaced the fermenting barrel.
11/ The fermenting is normally done in a converted fridge. I don’t open the bucket anywhere near the fridge; it’s always sealed and airlocked when in or near the fridge.
12/ Dry hopping, or not, doesn’t seem to make any difference to the outcome.

I’m getting fed up of this because it’s ruining brew after brew, despite my best efforts. Is the only solution going to be use fresh, dried yeast, every brew?

Any suggestions anyone?

[BenB]

Sure does sound like wild yeast. I was wondering about oxygenation but that's usually a process error that would occur with every brew.

If you re-use yeast it's a question of when rather than if an infection gets introduced. And the yeast qualities will change. I believe even in "proper" breweries they only re-use so many times.

What's the inside of the fridge like? I was getting problems with mould in my fermentation chamber until I got a chamber dehumidifier. Plastic FVs are permeable my moulds. Some anti-bac multi-surface wipe over the inside of the fridge and a dehumidifer might be of use... seems to have done the trick for me with my presumed yeast infections anyway....

Considering Brettanomyces comes from "British Fungus" it's surprising more people in the UK don't suffer with such infections in brewing!

[TheSumOfAllBeers]

Brett wouldn't work that fast, but you may also have a bacterial contamination too.

Boil everything that touches your beer. Put your plate chiller in the oven prior to use. Heat treat anything that can take it. Replace parts that can't take the heat.

Retire your plastic bucket FV.

Consider replacing with a stainless option, or expect to go through plastic buckets until you fully address the problem.

[serum]

It might be your mashing. If your ph is getting too high then you can end up with dry, bland beer. I had this problem but sorted it with water treatment.

I found it appeared after bottling as the haze was settling. Once it cleared it was like all the flavour had fallen out.

I also had some infections from poor handling of yeast. I was trying to grow from bottles and ballsed it up. I got a little sourness in with the tannic flavour.

[chrisr]

BenB
Yeast: yes, I know if you reuse it too many times, it isn’t a good thing. That’s not my intention. Things don’t get that far, they go wrong within a couple of brews. Obviously once I’ve had an infected brew, I have to chuck the yeast and start from afresh.
Cleaning the fridge: I never open the fermenting bucket near the fridge, but if it helped you, I shall certainly try cleaning the inside of my fridge.

TheSumOfAllBeers
Baking the plate chiller: a good idea, I will try that.
All that touches the beer cold-side is the plate chiller, the pipe from that to the FV, the FV itself and the oxygenating ‘stone’ (which is steel).
FV: I have replaced it. It didn’t seem to make any difference. I got one or two good brews, then the problem was back again. I have been thinking about stainless, but I haven’t found anything that would fit in my fridge! I do like having full control of the fermenting temperature. I can't afford one of the fancy all-singing-dancing stainless vessels with heating and cooling attached.

Serum
I don’t think it’s the mash, as I do just the same with the successful brews as contaminated ones.
The fact that with a fresh yeast, I almost always get one good brew has made me think ‘yeast management’. But I am struggling to pin down exactly what. As BenB has said, reusing yeast over a period will increase the chances of infection – but after one brew?

Something that puzzles me is how I can get one, two or even three good brews in a row and then the problem returns - where from? That's the big question.

I’m thinking there something I’m not seeing, which is why I posted on the forum: to get some fresh ideas. Thanks all, for the input so far.

[f00b4r]

Consider making a cheap kit so you are only then using a fv, the fermenting chamber a bottling bucket and a little bottler (?), this would then help rule out that part of the process.

[oz11]

What is your process for reusing yeast? This seems like the area to look at to me.

[serum]

From what you've said you're probably coming unstuck when you reuse your yeast.

It's nice not to have to buy yeast each time but when you're losing batches it makes sense.

Ive had no problems using white labs or wyeast yeasts when I make an oversized starter which I then save a bit of for the next beer. I think my problem was growing yeasts from unhealthy dregs.

You need to be careful if you're using a yeast cake or slurry, especially in the summer with fruit flies and the like. How are you doing that?

[chrisr]

Serum, considering the suggestions people have been offering, and possibly my actually writing the whole tale of woe down, I have been coming round to thinking along those lines, too.

The fact that the first brew with a fresh yeast always works is a bit of giveaway, isn’t it?

I think in the short term, it’s a fresh pack of dried yeast, every brew.



The brewery yeast is a top cropper. I discard the first krausen, usually day two, and collect the second, usually day three. I bring the FV into the house, still sealed, blast the whole area around it with starsan, then open the FV and scoop the krasuen off, using a plastic perforated spoon. Spoon and collecting basin are cleaned and starsanned before use. I then cover it with cling film and keep it in the household fridge.

If using the yeast cake, prior to racking off the brew I boil up a pan of water and let it cool. I add maybe a generous litre of boiled water to the cake, swill it round to break it up, and decant into kilner jar, put the lid on. I let that settle a bit, then decant the top part into another jar. It’s kept in the household fridge. Everything is starsanned.

If anyone has suggestions for improvements, fire away…

[BenB]

Do you make up the starsan spray bottle each time? The inside of spray bottles and FVs full of starsan can get mouldy above the water line unless you shake it frequently. Obviously the moisture that evaporates and condenses on the side walls is just water and has no sanitisation at all. So when you're spraying everything with Starsan you could potentially be innoculating stuff with mould.

When something like this was happening to me I went back to kits and built up from there over four to five brews.

[oz11]

Additionally, starsan is less than effective against wild yeast contamination. I'm in a position to get hold of it easily so I switched to peracetic acid and only use starsan occasionally.
When you use the brewery yeast is the first batch okay? It maybe the yeast from the brewery isn't as clean as it could be and they may well acid wash it before they pitch it.

[serum]

Hmm what you're doing sounds similar to what I do with my starters but you must have some gunk somewhere that's messing it up. Nothing is jumping out at me though.

I tend to leave my yeast in kilner jars in the fridge that are sprayed with star san as well and don't have a problem.

[BenB]

Rotating sanitisers is not a bad idea. I use VWP as a cleaner occasionally (instead of PBW) and got some povo-iodine to occasionally use instead of starsan. Otherwise as said you run the risk of just artificially selecting for some resistant strains to become prevalent.

[chrisr]

Some interesting points regarding the Starsan. I'll have to get hold of an alternative sanitiser, and swap for a while.

I did know Starsan doesn't kill wild yeasts - if it did, it probably wouldn't do the brewing yeasts any good, either!

I'm planning on brewing tomorrow. I've cleaned the fridge with a bleach solution, the FV has been cleaned with neat bleach and is now full of PBW-type cleaner. I will be baking the plate chiller before use. Perhaps most importantly, I'll be using a packet of S04. Fingers crossed then...

Thanks for the replies, everyone.

[BenB]

Good luck for tomorrow- do make sure the fridge is dry inside. My first attempt at cleaning my fermentation chamber made things worse by increasing moisture levels