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Pitching specific weight of dry yeast >11.5g <23.0g?

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slash22000

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I'm planning on making a beer, OG ~1.073, 22 litres. MrMalty says I should use 15g of dry yeast (assuming 100% viability).

Normally I'd just chuck in a 11.5g packet and hope for the best, but 15g is a fair amount over 11.5g and I doubt it's literally 100% viable (been refrigerated since day 1 etc but it has to lose some viability over time, surely).

What do people normally do in this situation?

  1. Two packets? It's a hoppy beer, I don't really want to overpitch
  2. One packet and 3.5g out of a second packet? Seems like a waste of money / yeast
  3. One packet and pray to Aegir, Norse God of beer?
  4. ???

I'm hoping one of you has some kind of solution to this issue that doesn't involve throwing money down the drain. Surely a solution exists. This is not an uncommon issue. :D Cheers all.
 

mckenry

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You really do need 15g. 11.5 is under-pitching by a quarter If it was me, I would go for option 2 and save the rest. Its bound to happen again. Just make it airtight and chuck in the freezer. I bought a 500g packet of US-05 once. Cheap in the long run and I could measure out exactly what my yeast calculator says.
 

razz

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Use two packets, and don't worry about overpitching.
 

squirt in the turns

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razz said:
Use two packets, and don't worry about overpitching.
+1

You could go with exactly what the calculator suggests, but preserving the half used packet is probably more hassle than it's worth and there's little harm in overpitching (which you barely would be anyway). It's generally much better to overpitch than underpitch anyway (some styles excepted).

What does it being a hoppy beer have to do with overpitching? If you overpitch you'll probably just get reduced ester production. You probably don't want/wouldn't even notice esters in a hop-forward beer anyway.
 

slash22000

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squirt in the turns said:
What does it being a hoppy beer have to do with overpitching?
I took that queue from Vinnie Cilurzo, head brewer of Russian River, that make stupidly famous hoppy beers, i.e. Pliny the Elder/Younger series.

I quote,

"Your pitch rate is one of the most critical factors when brewing an IPA or Double IPA. Too much yeast and you could end up with less bitterness due to the fact that the yeast takes up bitterness from the beer."

I assume he means that the yeast absorbs or somehow drops hop oils from the beer, so more yeast = less hops?
 

Nick JD

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slash22000 said:
I took that queue from Vinnie Cilurzo, head brewer of Russian River, that make stupidly famous hoppy beers, i.e. Pliny the Elder/Younger series.

I quote,

"Your pitch rate is one of the most critical factors when brewing an IPA or Double IPA. Too much yeast and you could end up with less bitterness due to the fact that the yeast takes up bitterness from the beer."

I assume he means that the yeast absorbs or somehow drops hop oils from the beer, so more yeast = less hops?
I'm not sure he knows what he means, either.
 

seamad

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Cell counts are not exact and will differ with different yeasts for eg windsor yeast is smaller than notto and therefore there are more windsor cells per gram than notto. Lager yeasts are bigger again so less of them per gram than ale yeasts. Different researchers come up with different cell counts too, notto has between 20 -30 billion cells per gram. If you take the higher figure then you will get your @300 billion cells from one packet, and pitching two maybe a massive overpitch if using notto.
Also cell numbers are dependent on rehydrating technique so you need to take that into consideration too.
Clear as mud now
cheers
sean
 

mckenry

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Just note slash, that 2 packets is over pitching by 50% and 1 packet is under by 25%

Just get it right if you can. Brewing great beer is about doing all the little things right.

Your question is that more yeast means you'll lose bitterness, which means you'll have to somehow work out how much more hops to add. More guesswork = more chance of failure.

The calculators exist because brewers need to get it right. No need to be crazy about it, but 15g is easy to do and will be far better than 11.5 or 23.
 

felten

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It probably won't be at 100% viability anyway. (once you learn the date on the packet)
 

squirt in the turns

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slash22000 said:
I took that queue from Vinnie Cilurzo, head brewer of Russian River, that make stupidly famous hoppy beers, i.e. Pliny the Elder/Younger series.

I quote,

"Your pitch rate is one of the most critical factors when brewing an IPA or Double IPA. Too much yeast and you could end up with less bitterness due to the fact that the yeast takes up bitterness from the beer."

I assume he means that the yeast absorbs or somehow drops hop oils from the beer, so more yeast = less hops?
I've never heard that before. It's said that volatile hop aroma compounds can be driven off by a vigorous fermentation, which overpitching could cause. Maybe that's what Vinnie Cilurzo is getting at, in that perceived bitterness decreases as hop flavour decreases? Although the wording "yeast takes up bitterness" doesn't really gel with that theory.

A Google search reveals that everyone has different ideas about what overpitching does. Lower esters is generally a given. But, as an example, this experiment found a dramatic increase in bitterness in the overpitched sample.
 

felten

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It's my understanding that iso-alpha acids are essentially sticky, they stick to the yeast cells and are removed with the yeast. The more cells there are, the more surface area there is for this to take place.

How much affect this will have for Slash, I don't know. But It's something I've heard commercial brewers talk about before.
 

stakka82

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^^^ i have read this also, and anecdotally i have noticed clearer (gelatined) similar beers brewed a certain IBU seem less bitter than ones i have not gelatined, or even the same batch before and after yeast drops out.

disclaimer: conjecture
 

bum

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I recall reading Coopers claiming that yeast can pull out as much as 30% of total IBU. Not entirely sure I believe that but the idea is not novel.
 

slash22000

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So it seems as with anything to do with brewing, the general consensus is "There is no consensus". :D

I'm not super happy about adding ~10% to the cost of making a batch by spending another $4.50 on a second pack of yeast, but I'd prefer that to wasting 100% of the cost if underpitching fucks the whole batch up.
 

bum

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$4.50 divided by how many bottles?
 

wbosher

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I'm not super happy about adding ~10% to the cost of making a batch by spending another $4.50 on a second pack of yeast, but I'd prefer that to wasting 100% of the cost if underpitching fucks the whole batch up.
I think you pretty much answered your own question right there.
 

Nick JD

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Underpitching will be fine.

The yeast will breed up to the same amount regardless of a few percent over or under. You avoid underpitching not to curb cell count, but to avoid undesirable flavours.

The oxygen level and the OG will determine the amount of yeast.
 

slash22000

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Nick JD said:
Underpitching will be fine.

The yeast will breed up to the same amount regardless of a few percent over or under. You avoid underpitching not to curb cell count, but to avoid undesirable flavours.

The oxygen level and the OG will determine the amount of yeast.
I was under the impression that stressing the yeast is what caused undesirable flavours. Wouldn't underpitching stress the yeast even with enough oxygen being supplied? Or else why have a recommended pitching rate at all? :blink:
 

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