How much yeast ?

[IPA]

I've been using wet yeast for many years now. In fact one particular strain WLP 037 I have been reusing since 2013. Anyway, the last brew day but one I tasted the starter before pitching and to my horror it was infected. I usually keep some dried yeast in the brew fridge for this event but upon searching I discovered that I had only one packet of SafAle S-04 due to the fact that I had recently given away several packets.
So I had 57 litres of wort in the fermenter and one packet of 11.5grs of yeast. The recommended dose for this amount is between 25-40 grs.
With no choice I sprinkled the yeast on top of the wort and closed the lid.
Within two hours the krausen was forming and from then on fermentation proceeded as normal and the beer turned out fine.
Considering WhiteLab recommend using three packs of WLP 037, at a cost of £13 each, for this brewlength are we being misled ?

[guypettigrew]

Well, Mr IPA, looks like your post, and the query in it, has completely befuddled all of us JBK'ers.

I have no answer at all. Whatever yeast I use there has never been a Krausen after two hours. Even fresh, wet yeast, which I've grown in a starter for a few days.

We need Nallum's view on this!

Guy

[IPA]

Well, Mr IPA, looks like your post, and the query in it, has completely befuddled all of us JBK'ers.

I have no answer at all. Whatever yeast I use there has never been a Krausen after two hours. Even fresh, wet yeast, which I've grown in a starter for a few days.

We need Nallum's view on this!

Guy

It wasn't a one off ! I have just repeated it with the same result.

[nallum]

That's a shame, about the WLP037. Let me know if you want some of mine. Not sure if it's easily available in Europe now, even when 'the vault is open'.

As far as the observations for the pitched dry yeast go, not that surprising. I'd guess it was a 'sensible' OG and oxygenated well. Leaving it open would have helped supply sufficient O2 for the yeast too, to multiply and occupy all that nutritious wort too. But it took a bit longer than expected? The early 'krausen' was likely misleading and more to do with dry yeast hydrating on top and just getting a bit 'fizzy' locally, rather than a reliable signal of what was going on throughout the wort generally. Dry yeast do that when sprinkled in water too.

Of course, it 'works', but how does it compare? A lot of what we do, in terms of pitching good practice, comes down to increasing probability therefore better standardisation - fewer risks and consistency. Then there's what the actual yeast strain used adds.

[IPA]

Thanks for the input Nallum. I am sure you are correct about appearance of the krausen. Also many thanks for the offer of some yeast. But I still have samples of 037 from 2013,2018 and I have just ordered their last 2025 version of 037 from Brouwland
Ian

[guypettigrew]

This a couple of months old now, but what's the conclusion?

Is one 11g pack of dried yeast enough for 23 litres of wort at about 1.050?

Have we, as Ian said, been misled?

Guy

[nallum]

Why would yeast suppliers mislead by giving too much yeast in a pack? The opposite is closer to the truth. They should double what they put in a pack, to promote a more predictable fermentation.

One data point/personal experience doesn't represent what's most probable in the average experience. It's easy to misinterpret observations.

I spent a couple years comparing dry vs wet (repitched) yeast meaningfully, by actually measuring things. The trend was unmistakable. I couldn't recommend dry yeast unless repitched at a much higher cell density.

What 'works' in opinion is primarily based on what we're prepared to accept as "it worked".

Home brewers have been encouraged to pitch using different advice to what professionals are given. A business decision made by yeast suppliers. Pitching more - healthy - yeast isn't simply a business decision based on "time is money ". It produces consistently better beer.