Re-Hydrate v Not..

[Feldon]

If what you say is true then dry pitching (close to double the 'normal' amount, mind you) would in fact be better then re-hydrating.

That'd be sort of funny in the context of this thread.

Double dose of yeast is probably not needed. Yeast multiply in the early stages so I reckon the numbers are soon made up.

Many nutrients from the dead cells are ready-made for use by the surviving yeast - they don't need to use the oxygen in the wort to synthesise the molecules anew. Takeaway meals for yeasties.

 

[Florian]

Double dose of yeast is probably not needed. Yeast multiply in the early stages so I reckon the numbers are soon made up.

I know, I didn't want to get Slash to start preaching again though by not stressing that point.

Also in context of the comparison I made:


one pack of rehydrated yeast = one pack surviving yeast
Two packs of dry yeast = 1 pack surviving yeast + nutrients + better 'gene pool' (as only the 'strong ones' survive)

I know those numbers and probably the whole theory is flawed in many ways, was just trying to show Slash that dry pitching can be in fact better than re-hydrating, tongue in cheek (just a little, though).

EDIT: Clarity

 

[GalBrew]

Double dose of yeast is probably not needed. Yeast multiply in the early stages so I reckon the numbers are soon made up.

This is called underpitching and has a noticable affect on beer flavour.

 

[Feldon]

This is called underpitching and has a noticable affect on beer flavour.

Read (and understand) my post. Ta.

 

[Feldon]

I know, I didn't want to get Slash to start preaching again though by not stressing that point.

Also in context of the comparison I made:

one pack of rehydrated yeast = one pack surviving yeast
Two packs of dry yeast = 1 pack surviving yeast + nutrients + better 'gene pool' (as only the 'strong ones' survive)

I know those numbers and probably the whole theory is flawed in many ways, was just trying to show Slash that dry pitching can be in fact better than re-hydrating, tongue in cheek (just a little, though).

Yep, agree. Two packs probably even better. But for me one pack is fine.

 

[GalBrew]

Read (and understand) my post. Ta.

I did. You are saying that double dry pitching is not required due to the super powers that the remaining viable yeast will get from their dead sachetmates. Yes, yeast will multiply. This is still underpitching. Ta.

 

[slash22000]

If I'm "preaching" the benefits of rehydrating then so is every single microbiologist who has ever done any non-biased scientific research into this topic. We'll have to inform their colleagues so they can immediately be stripped of their qualifications and expelled onto the street. -_-

"You're all wrong! All your research is wrong! All your conclusions are wrong!"

"What!? Why!?"

"Some guy said so. He reckons you're wrong."

"What proof does he have!? I've spent decades in microbiology, my tests were conclusive and repeatable!"

"Well, he doesn't have proof, really. He just disagrees."

"Why!?"

"Just because. Stop preaching your 'facts' you loons. Respect his authoritah."

"..."

 

[pcmfisher]

To me dry pitching has a slight flavour muddle. Like hearing very light static on radio station that's slightly off station. If that makes sense.

Good comparison. They are probably both in you head.

 

[Black Devil Dog]

Next weeks topic for debate, temperature control or no temperature control. h34r:

 

[slash22000]

Given the results of this thread I guess most people will be arguing against temperature control too because technically it's unnecessary. Time after that we'll be arguing against brewing at all. Go back to drinking water.

 

[WarmBeer]

Next weeks topic for debate, yeast or no yeast. h34r:

FTFY.

 

[Florian]

If I'm "preaching" the benefits of rehydrating then so is every single microbiologist who has ever done any non-biased scientific research into this topic. We'll have to inform their colleagues so they can immediately be stripped of their qualifications and expelled onto the street. -_-

Not sure if you've read my posts but we're mainly on the same page in regard to the theoretical science (and only that part).

'Preaching' refers to you posting the same stuff in this thread over and over and over again with a seriousness that just reminded me of preaching. No offence meant, but if you read over your last ten or so posts you might know what I mean.

In saying that, at least one of the 'scientists' you quoted and referred to a couple of times in this thread I would not call completely unbiased as he is in fact a direct competitor to all dry yeast manufacturers.

EDIT: Can you tell I'm extremely bored? Better leave that computer alone for a while and do something productive. Already brewed today so will have to find something else.

 

[Feldon]

I did. You are saying that double dry pitching is not required due to the super powers that the remaining viable yeast will get from their dead sachetmates. Yes, yeast will multiply. This is still underpitching. Ta.

Ok.

We all underpitch to the extent that the yeast we pitch in always insufficient on its own to ferment the wort to completion.

What we rely on is the oxygen in the initial wort to help the yeast to reproduce. That's why we aerate or oxygenate the wort. Importantly, the pitched yeast consume the oxygen to synthesise lipids (chemical group = oils, fats, waxes) which are used to make cell walls for daughter cells.

There is a limit to this. Once all the free oxygen is consumed the yeast numbers are up but they then have difficulty in reproducing (making building blocks for new cell walls).

1. If you rehydrate your pitching yeast and aerate normally the yeast will consume the available oxygen and multiply to achieve the numbers needed to ferment out your beer to completion.

2. If you direct pitch the yeast, half die (or thereabouts but just sayin). The remaining yeast will also consume the oxygen in the wort to multiply. But they also have at hand the ready-made biomolecules including lipids and other tasty morsels from their dead brethren to increase their numbers. The number of cells these lipids can provide I reckon to be roughly the same as the number of cells that died at pitching (sort of biochemical equilibrium).

All ends up pretty much at the same place really. Except you've executed all those inferior yeast cells that haven't got the balls to do a good job at fermenting beer anyway.

All yeast are not created equal.

 

[Silver]

Me thinks an experiment is brewing. We have everything we need. Passionate brewers, expert tasters. Great excuse for 3 sessions. The brew, the bottle and the tasting. It would also be interesting which batch dropped to 1040/1030/1020/1010 quicker. Just a thought.

 

[spudfarmerboy]

If I'm "preaching" the benefits of rehydrating then so is every single microbiologist who has ever done any non-biased scientific research into this topic. We'll have to inform their colleagues so they can immediately be stripped of their qualifications and expelled onto the street. -_-

"You're all wrong! All your research is wrong! All your conclusions are wrong!"

"What!? Why!?"

"Some guy said so. He reckons you're wrong."

"What proof does he have!? I've spent decades in microbiology, my tests were conclusive and repeatable!"

"Well, he doesn't have proof, really. He just disagrees."

"Why!?"

"Just because. Stop preaching your 'facts' you loons. Respect his authoritah."

"..."

I rehydrate most times, but gees Slash, you do crap on a bit.
If people don't want to rehydrate, who cares, if you and I want to, fair enough.
You seem to be on an evangelical crusade.

 

[spudfarmerboy]

Feldon, you mention oxygenating the wort. Some dried yeast manufacturers such as Lallemand say you don't need to oxygenate when using their dried yeasts.
Edit - Lallemand say oxygenating or aerating is not necessary when rehydrating their yeast.

 

[sponge]

Hallelujah!

 

[GalBrew]

Ok.

We all underpitch to the extent that the yeast we pitch in always insufficient on its own to ferment the wort to completion.

What we rely on is the oxygen in the initial wort to help the yeast to reproduce. That's why we aerate or oxygenate the wort. Importantly, the pitched yeast consume the oxygen to synthesise lipids (chemical group = oils, fats, waxes) which are used to make cell walls for daughter cells.

There is a limit to this. Once all the free oxygen is consumed the yeast numbers are up but they then have difficulty in reproducing (making building blocks for new cell walls).

1. If you rehydrate your pitching yeast and aerate normally the yeast will consume the available oxygen and multiply to achieve the numbers needed to ferment out your beer to completion.

2. If you direct pitch the yeast, half die (or thereabouts but just sayin). The remaining yeast will also consume the oxygen in the wort to multiply. But they also have at hand the ready-made biomolecules including lipids and other tasty morsels from their dead brethren to increase their numbers. The number of cells these lipids can provide I reckon to be roughly the same as the number of cells that died at pitching (sort of biochemical equilibrium).

All ends up pretty much at the same place really. Except you've executed all those inferior yeast cells that haven't got the balls to do a good job at fermenting beer anyway.

All yeast are not created equal.

Quite right in terms of what we call a 'correct pitch' is infact an underpitch. It is however a calculated underpitch which results in the degree of yeast growth required for a desireable level of flavour compounds in the beer. Just like if you overpitch massively you will not get any cell budding and while fermentation will occur no problems, you will not acheive the desired flavour profile from the yeast.

You are however assuming that the 50% or thereabouts of yeast that die following dry pitching is due to some sort of natural selection of the 'fittest; yeast. This may be the case however it may also be due concentration gradients in the wort of whatever? Who the hell knows? I do agree that the 50% of dead yeast will probably serve as nutrient, but you will still end up with excess esters due to increased replication.

 

[Feldon]

Feldon, you mention oxygenating the wort. Some dried yeast manufacturers such as Lallemand say you don't need to oxygenate when using their dried yeasts.

I said "aerate normally" - whatever your usual process is for whatever yeast your using.

Wort at ferm temp has some oxygen in it to start with, even if freshly cooled from the boil and has stuff all.

If the yeast maker says don't aerate, then don't - up to you. Doesn't change the basic idea of what I posted.

 

[Feldon]

You are however assuming that the 50% or thereabouts of yeast that die following dry pitching is due to some sort of natural selection of the 'fittest; yeast. This may be the case however it may also be due concentration gradients in the wort of whatever? Who the hell knows?

Yeah, there must be something determining which yeast cells get the chop and which get to eat my nice sweet wort. They can't be all the same. Some die some don't.

My money is on the yeast being of widely varying viability, and is over supplied in the sachet by the yeast maker with this in mind. So even after an attrition rate of 50% you can still make good beer.

I can also understand, as Ross said, the economic imperatives of running a commercial brewery where rehydrating can save on costs.

(Also aware that a common marketing ploy is to get consumers engaged and invested with their product by spending more time with it. Which is what we do with rehydration. Bit like Coopers telling us to roll a stubby of across the bar before drinking it to mix up the yeast. But that's just me and my suspicions of corporate agendas)