Excessive yeast growth

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McMullan

Re: Excessive yeast growth

Post by McMullan » Tue Oct 10, 2017 7:06 pm

About 10ppm. To achieve that you'd need an O2 meter, really. I don't have an O2 meter. Like others, I gently bubble pure O2 while stirring for 1min; but, depending on the flow rate, it's an 'how long is a piece of string' guesstimate. What works for you is best determined empirically.

edit: 10ppm is about the optimal. Above 10ppm, the risk of compromising ethanol production (due to a shift to biomass production) starts. (Commercial yeast are often grown under constant O2 conditions mainly for this reason.)

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Re: Excessive yeast growth

Post by PeeBee » Tue Oct 10, 2017 8:25 pm

McMullan wrote:
Tue Oct 10, 2017 7:06 pm
About 10ppm. To achieve that you'd need an O2 meter, ...
Hum. You, and many others, are quick to suggest I've "over-oxygenated" and also "over-pitched". Maybe, but unless I know how folk arrived at that idea I'm no nearer to correcting it. I might of under-oxygenated, or under-pitched? This one-minute-blast-of-O2-for-25-litres might be complete nonsense? The online Pitch Rate Calculators might be complete nonsense?

I'll be trying a 45 second blast of O2 in my next brew. I'll grow my yeast for a 0.5-million-cells/ml/degree-Plato next time too; good, I should be able to do that in one step. This, and the previous brew (that got 120 seconds of O2, but didn't cause any of these problems: Wyeast-1099, bigger gravity, bigger pitch rate), all seem fine - no odd tastes detectable.

I post all this stuff in the hope of helping others. Unfortunately I think I've failed here and I may be putting folk off giving pure oxygen a try and switching to liquid yeasts from dried. Folk can't even learn from my mistakes, because any mistakes I may of made can't be quantified. It's a case of "try this ... but you're on your own".
Cask-conditioned style ale out of a keg/Cornie (the "treatise"): https://drive.google.com/file/d/0BwzEv5 ... rDKRMjcO1g
Water report demystified (the "Defuddler"; removes the nonsense!): https://drive.google.com/drive/folders/ ... sp=sharing

McMullan

Re: Excessive yeast growth

Post by McMullan » Tue Oct 10, 2017 9:36 pm

There is no definitive answer, in reality. It depends on the wort and the yeast strain. O2 solubility declines with increasing wort gravity. Ale strains can have low, medium or high O2 requirements. 10ppm was determined as 'optimal' under laboratory conditions. In brewing, things are a lot more variable. Most professional Brewers work with one yeast culture and the O2 requirement (and pitching rate) is determined empirically, over several fermentations. The 1 minute 'simmer' of pure O2 is predicted to get about 10ppm in solution for a 1.060 standard batch. Depending on yeast strain, a low gravity wort might require 30 seconds or less. A high gravity wort might require 2 minutes or more. It isn't possible to provide a one-size-fits-all approach. Brewing is far too diverse for that kind of prescription. I got my pure O2 setup about a year ago. It was intended for higher gravity worts, but I use it for all worts now. It's much easier than shaking full FVs, which I did for years with few issues, ignoring the occasional back ache.

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Kev888
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Re: Excessive yeast growth

Post by Kev888 » Wed Oct 11, 2017 11:33 am

The behaviour of the fermentation doesn't seem especially unusual to me. Early vigour is fairly typical for wlp002 - it was probably a little more abrupt than normal in this case but thats likely due to the somewhat warm temperature - it is fairly sensitive to temperature IMO, and also tends to generate lots of heat itself. (In some systems the latter may create a higher than appreciated temperature differential between wort and sensor, too). The FG is also within my expectations - it depends on your recipe and mash conditions, but can reach 80% apparent attenuation if wished (irrespective of whitelab's rather nominal quoted range), it is very flexible.

The amount of slurry WLP002 produces in short order is usually healthy, and can be exaggerated by combining with other stuff from the wort - especially if it has worked quickly, whilst things like cold break are still settling. I prefer not to let it build up too much before first dumping, partly to avoid it becoming too compacted and partly because I want all the early stuff long gone before harvesting clean slurry after FG.

These are my experiences based on using (filtered) air to oxygenate: this is unlikely to achieve too much beyond 8ppm dissolved oxygen, certainly it won't be over-oxygenated by any normal definition. My pitching rate is perhaps a little high - I shoot for an estimated 0.75 million cells per ml per degree plato but can only estimate the cell numbers so am likely to be a little over. That target is not unusual for ale yeast, but it is also a matter of preference - British beers are often purposely pitched with fewer cells in order to encourage more yeast character in the beer; I keep meaning to try this with WLP002, it has a nice flavour and very few reliability issues if not used cool, so suspect it could do very well.
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Re: Excessive yeast growth

Post by HTH1975 » Wed Oct 11, 2017 12:15 pm

Is this pure-oxygen technique not overthinking the situation? Both of the breweries I’ve worked at did nothing more than let the wort splash into the FV from the top.

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Re: Excessive yeast growth

Post by PeeBee » Wed Oct 11, 2017 12:46 pm

Kev888 wrote:
Wed Oct 11, 2017 11:33 am
The behaviour of the fermentation doesn't seem especially unusual to me. ...
Thanks Kev. I'm beginning to think I setup the "perfect storm" and I shouldn't get a repeat of it. I'll pitch a couple of degrees cooler next time, and cap a couple of degrees cooler too. I'll pitch less yeast and oxygenate less too. I'll do as you do and dump a portion early so the yeast build up can't become a problem. I hear what you say about "encouraging more yeast character", I was already suspecting that using these "American" tools for guesstimating probably isn't the best idea (unless brewing in the "American" style).

The over-attenuation should be interesting. I would normally use Safbrew S-33 on this formulation which finishes very early (about 1.018-20). Only it doesn't finish, it just takes an extended nap and when it wakes up a couple of months later starts to really mess up the carbonation levels in the keg.

The troublesome beer is calm and safe now, so I don't feel quite as despondent as yesterday.
Cask-conditioned style ale out of a keg/Cornie (the "treatise"): https://drive.google.com/file/d/0BwzEv5 ... rDKRMjcO1g
Water report demystified (the "Defuddler"; removes the nonsense!): https://drive.google.com/drive/folders/ ... sp=sharing

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Re: Excessive yeast growth

Post by PeeBee » Wed Oct 11, 2017 1:10 pm

HTH1975 wrote:
Wed Oct 11, 2017 12:15 pm
Is this pure-oxygen technique not overthinking the situation? Both of the breweries I’ve worked at did nothing more than let the wort splash into the FV from the top.
I would have said so a few years back. But this brewery doesn't "splash". It pumps to sub-surface inlets. The fermenter makes manual agitation (with a spoon) very difficult; picking it up and shaking it is a non-starter (75+ Kgs). I used to use an air pump, filter and stone and a right pain that was. Pure oxygen is cheap and extremely simple, needing just a few seconds.

But guidance for using it (pure oxygen) is a bit thin on the ground, and being nearly 100% oxygen there's no partial pressure effect to prevent over- doing it.
Cask-conditioned style ale out of a keg/Cornie (the "treatise"): https://drive.google.com/file/d/0BwzEv5 ... rDKRMjcO1g
Water report demystified (the "Defuddler"; removes the nonsense!): https://drive.google.com/drive/folders/ ... sp=sharing

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Re: Excessive yeast growth

Post by orlando » Wed Oct 11, 2017 2:23 pm

HTH1975 wrote:
Wed Oct 11, 2017 12:15 pm
Is this pure-oxygen technique not overthinking the situation? Both of the breweries I’ve worked at did nothing more than let the wort splash into the FV from the top.
Breweries are usually working with the same strain and regularly repitching within days of being recovered. The health of their yeast should be towards the top end. Quite a lot of home brewers, sometimes work with many yeast, that may have been stored for a long time. It's this yeast that really requires a little more TLC. Even if you are working with bought yeast (liquid) it can sometimes be close to its best before date and again requires a little help to get it ready for the job.
I am "The Little Red Brooster"

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Re: Excessive yeast growth

Post by Kev888 » Thu Oct 12, 2017 1:42 am

There is little doubt that pure oxygen is more effective at raising dissolved oxygen levels. Useful with the more oxygen-loving strains and especially so for high gravity brews. Air can only impart a limited amount of oxygen and can take longer to do so; it can be necessary to cope with foam-overflows as a result of the extra bubbling/splashing.

On the other hand pure oxygen is harder to judge and could potentially go too far, whereas (for normal beers) air will top out at a roughly appropriate level if given long enough. Oxygen cylinders are at least potentially dangerous and involve a small but ongoing cost, whereas any amount of air is free and relatively safe.

Personally I aspire to oxygen but the extra gubbins would be inconvenient at the moment. I would also only like to go there with a DO meter in addition to the cylinder, regulator etc., so it is squarely in my 'for the future' category. It isn't a priority for me; no normal gravity beer or yeast would typically struggle with a decent amount of aeration (and dried yeast hardly care).
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Re: Excessive yeast growth

Post by orlando » Thu Oct 12, 2017 7:57 am

If it wasn't for oxygenating my wort I would go back to buying my yeast for each brew, splashing would do and I can do it without dragging in air from outside my conical. The effect is that important in my experience. There is no single magic bullet in brewing but there are certain links in the chain that without them introduce a compromise. Repitching yeast is a choice but if you do it and there is a significant delay between use, then oxygenating becomes one of those links. You don't need pure O2 but it is a lot quicker and easier than any other method. The overhead is reasonably high to begin with but my O2 bottle will probably last me for life. :D
I am "The Little Red Brooster"

Fermenting:
Conditioning:
Drinking: Southwold Again,

Up Next: John Barleycorn (Barley Wine)
Planning: Winter drinking Beer

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Re: Excessive yeast growth

Post by PeeBee » Thu Oct 12, 2017 10:51 am

Kev888 wrote:
Thu Oct 12, 2017 1:42 am
... whereas any amount of air is free and relatively safe.

Personally I aspire to oxygen but the extra gubbins would be inconvenient at the moment. I would also only like to go there with a DO meter in addition to the cylinder, regulator etc., so it is squarely in my 'for the future' category. It isn't a priority for me; no normal gravity beer or yeast would typically struggle with a decent amount of aeration (and dried yeast hardly care).
Thanks. If it helps you to decide:

I made my decision to swap to pure oxygen because "any amount of air" ISN'T free! Well not if you are filtering it to keep bacteria out. The filters were expensive at about £3.25 a shot (I did reuse them, so two shots, but dodgy, and if they got at all wet that was the end of them). The filters were quite big (for hospital breathing apparatus), required much bodging to adapt them, and my supply of cheap "out-of-date" ones dried up. I needed big to take the flow (40-70L batches, but I don't consider the little syringe filters to be any good for smaller batches either), but they could still explode due to pressure (car tyre pump, anything less and the air would not pass the 2um sintered SS air stone).

DO meters would be great, but are flippin' expensive! As Orlando says, bit of an upfront cost for the cylinder deposit, but ongoing cost is probably zero. What you said about air being relatively safe; yes I suppose O2 is a hazard, the high pressure cylinder for one, and although O2 is NOT flammable, everything in its presence becomes a heightened fire risk.

"In addition to cylinder, regulator etc.", well "etc." only means an air stone and some tubing. Although you can add a flow meter (couple of quid off EBay) if you really want.
Cask-conditioned style ale out of a keg/Cornie (the "treatise"): https://drive.google.com/file/d/0BwzEv5 ... rDKRMjcO1g
Water report demystified (the "Defuddler"; removes the nonsense!): https://drive.google.com/drive/folders/ ... sp=sharing

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Kev888
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Re: Excessive yeast growth

Post by Kev888 » Thu Oct 12, 2017 11:19 am

Strange, the little syringe filters work very well for me and 65L batches. Probably the pump pressure is important, the little aquarium pumps do struggle but a small 'nail art' airbrush compressor works extremely well. (The filter I have can be autoclaved in a pressure cooker; it is possible that capping it after use would be sufficient day-to-day, but I prefer to be sure).

I'm not suggesting that this is better than oxygen, and I will go there one day. I just raised it because of relevance to this thread, it means I'm confident in not having over-oxygenated in the absence of a DO meter.
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Re: Excessive yeast growth

Post by PeeBee » Thu Oct 12, 2017 11:42 am

Kev888 wrote:
Thu Oct 12, 2017 11:19 am
... The filter I have can be autoclaved in a pressure cooker; ...
Don't! I don't want to know. I've made my choice now and suitable alternatives is the last thing I need to know about...

I'm considering a DO meter, arguing to myself that I can justify it on the "for the good of the community" basis. Guidance on pure oxygen use is a bit thin on the ground, therefore there must be the opportunity to do something about it. I know there is too many variables for definitive advise, but I wish I could dig up enough "rule-of-thumb" advise to make a confident start (although I did make a confident start oblivious to the near catastrophes it was going to cause me despite 40+ years experience of brewing).
Cask-conditioned style ale out of a keg/Cornie (the "treatise"): https://drive.google.com/file/d/0BwzEv5 ... rDKRMjcO1g
Water report demystified (the "Defuddler"; removes the nonsense!): https://drive.google.com/drive/folders/ ... sp=sharing

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Re: Excessive yeast growth

Post by PeeBee » Thu Oct 12, 2017 12:51 pm

Handy article? Well geeky though.

https://www.morebeer.com/articles/how_yeast_use_oxygen

But need to be careful how it's used: It is not a sweetie jar that you pick out the bits you like, I see that mistake repeated a lot in these forums. (EDIT: I make that mistake too!).

Basically it tells me it would have been better to err on the low side (oxygenating and pitch rate), not the high or even the supposed "optimum". Although that could probably be deduced from these discussions on the forum anyway.
Cask-conditioned style ale out of a keg/Cornie (the "treatise"): https://drive.google.com/file/d/0BwzEv5 ... rDKRMjcO1g
Water report demystified (the "Defuddler"; removes the nonsense!): https://drive.google.com/drive/folders/ ... sp=sharing

McMullan

Re: Excessive yeast growth

Post by McMullan » Thu Oct 12, 2017 11:06 pm

How can you be better off avoiding the optimum, or somewhere at least close to it?

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