g-star

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Got to thinking about this after a discussion with another brewer, maybe I'm off base, maybe not. The theory:

Yeast require oxygen for healthy replication. The smack packs are not gas permeable, thus starting the yeast by bursting the "nutrient pouch" results in less than optimal yeast health, as the cells that survive have been oxygen deprived to a certain extent.

By inflating the smack pack prior to pitching and/or making a starter, do we inadvertantly propagate the less healthy yeast cells? Does this have an effect on the final beer, relative to an "unsmacked" pack?

I'm not convinced one way or another, but would like to get some thoughts.

bja

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I don't use Wyeast because I hate those smack packs, but if you're pitching without making a starter it does have an effect on the beer because you're underpitching.

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Life is tough. It's tougher if you're stupid.

TyTanium

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They're not designed to get cells to replicate; it's not like a starter.

It's just a nutrient pack to get them metabolizing and ready to roll. And proof viability.

jetmac

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+1

It's to give you piece of mind your yeast are alive. It's why alot of brewers (especially new brewers) don't like to use White labs. Because there is no way to ensure viabilty prior to pitching

So ya, you're off base.

And I don't think yest need oxygen to survive

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Wayne Gretzky-"100% of the shots you don't take, don't go in

Revvy>>You shouldn't worry about ANYTHING, you didn't hurt the yeast, they know what they need to do, they want to eat all that sugar they are swimming around in. They want to pee alcohol and fart co2, it's their nature.

Bobby_M>>I flood the keg with CO2 for one minute with the lid off, rack the beer in to the bottom gently, seal it, flood it, vent it. If there's still O2 in there after that, F it.

Airborneguy

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I came here to post what TyTanium just said. Smack packs are not designed to take the place of starters. The lack of oxygen is actually important: yeast should not be in an oxygenated environment unless they are in the growth stage. This will occur once you pitch.

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Kegged: Unintentional Sour Brown
Bottled:
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Scripts

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I think they say on their site that they recommend starters as opposed to just smaking, which would solve the o2 problem. The packs are only good in beers up to 1.050 too if i remember right. Not sure if that is to do with just the cell count or if they're accounting for lack of growth in the short period their active after the smack as opposed to being on a stir plate?

g-star

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Thanks, but I fully understand the importance of starters and pitch rates.

However, by breaking the seal of the smack pack the yeast begin to replicate and give off CO2, which causes the pack to inflate. My question has more to do with this principle:

Is it non-ideal to begin with yeast cell growth that is in a non-oxygenated environment? By "getting them metabolizing and ready to roll", is that not the same as introducing the cells to a sugar source and various nutrients (and thus replication)?

TyTanium

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You're not beginning yeast cell growth. Replicate and metabolize are different. That's my understanding at least.

Airborneguy

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They aren't growing in an anaerobic environment. They are feeding, ie, warming up for your wort. Replication only occurs in the presence of oxygen.

__________________
Fermentor(s):
Lagering:
Kegged: Unintentional Sour Brown
Bottled:
Tapped: Midnight Wheat
Up Next: IPA

Reading: 100 Battles

jetmac

Recipes 

They do not.

Yes it is "non-ideal" but they won't "grow" without oxygen.

It depends on what you are using to "getting them metabolizing and ready to roll"

__________________
Wayne Gretzky-"100% of the shots you don't take, don't go in

Revvy>>You shouldn't worry about ANYTHING, you didn't hurt the yeast, they know what they need to do, they want to eat all that sugar they are swimming around in. They want to pee alcohol and fart co2, it's their nature.

Bobby_M>>I flood the keg with CO2 for one minute with the lid off, rack the beer in to the bottom gently, seal it, flood it, vent it. If there's still O2 in there after that, F it.