[syncopadence]

So they say for a five gallon batch of up to 1.048 wort you only need 1 packet of yeast with no starter. However Beersmith calculates a starter with 1 pack, or 3 with no starter. What gives?

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[Big Monk]

So they say for a five gallon batch of up to 1.048 wort you only need 1 packet of yeast with no starter. However Beersmith calculates a starter with 1 pack, or 3 with no starter. What gives?

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Obvious questions first:

1.) is your fermenter volume 5 gallons in BS?
2.) is your gravity estimate 1.048 in BS?

How about the date? Is it fresh yeast? If viability is down, you may need a lot of yeast for a direct pitch.

[Robert]

Yeah, they say 1 pack no starter will give you a typical, old school, homebrew pitch rate -- which is generally grossly underpitching, but you can get away with it (maybe.)  Go with the recommended starter, and your results will be far superior, with not only more yeast, but much of it will be fresh, new-grown yeast in good health.  For this reason (growing fresh yeast) a starter is better, not to mention cheaper, than just pitching more packs off the shelf.

[syncopadence]

So they say for a five gallon batch of up to 1.048 wort you only need 1 packet of yeast with no starter. However Beersmith calculates a starter with 1 pack, or 3 with no starter. What gives?

Sent from my VS995 using Tapatalk

Obvious questions first:

1.) is your fermenter volume 5 gallons in BS?
2.) is your gravity estimate 1.048 in BS?

How about the date? Is it fresh yeast? If viability is down, you may need a lot of yeast for a direct pitch.

Yes and yes to 1 and 2. It's only 2 months old so it's still good. Curious why White Labs says I wouldn't need a starter, but BeerSmith says I would.

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[syncopadence]

Here's what I'm talking about, and the calculation is based on a 1.048 wort. Weird.

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[Big Monk]

So they say for a five gallon batch of up to 1.048 wort you only need 1 packet of yeast with no starter. However Beersmith calculates a starter with 1 pack, or 3 with no starter. What gives?

Sent from my VS995 using Tapatalk

Obvious questions first:

1.) is your fermenter volume 5 gallons in BS?
2.) is your gravity estimate 1.048 in BS?

How about the date? Is it fresh yeast? If viability is down, you may need a lot of yeast for a direct pitch.

Yes and yes to 1 and 2. It's only 2 months old so it's still good. Curious why White Labs says I wouldn't need a starter, but BeerSmith says I would.

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Keep in mind that 2 month old yeast is only 60% viable.

For 1.00 M/ml/°P on a 12 °P wort of 18.93 liters, you’d need about 227 B cells. With 100% viable yeast (which not even WL guarantees), youd be looking at 2 packs right off the bat to hit 227.

3 packs at 60% viability is 216 B cells. Not that far off.

All of this is irrelevant of course (the estimation of direct pitch amounts I mean) without actually counting the yeast to find the cell density in the package. I’d go with 1 pack with a starter.

Even if it was fresh off the line, WL only guarantees 95% viability, so pitching one pack would be:

( 120 * 0.95 ) = 114 B cells -> ( 114 / 12 ) / 18.93 = 0.50 M/ml/°P

[KellerBrauer]

Adding to this discussion, which BTW contains very sound information, is that yeast is relatively dormant when it’s in its packaging.  It needs to become active in order to do its job in your wort.  So, to make it active, we make a starter about 24-36 hours before pitching.  So, in addition to what’s stated above, this starter allows the yeast to prepare for its work drastically shortening the dreaded “lag time” prior to a vibrant fermentation.

Chris White, the founder of White Labs, details this very needed practice in his book simply titled: “Yeast”, A  practical Guide to beer fermentation.

[Big Monk]

Adding to this discussion, which BTW contains very sound information, is that yeast is relatively dormant when it’s in its packaging.  It needs to become active in order to do its job in your wort.  So, to make it active, we make a starter about 24-36 hours before pitching.  So, in addition to what’s stated above, this starter allows the yeast to prepare for its work drastically shortening the dreaded “lag time” prior to a vibrant fermentation.

Chris White, the founder of White Labs, details this very needed practice in his book simply titled: “Yeast”, A  practical Guide to beer fermentation.

One of the reasons why I prefer Wyeast. I think an activator pack(s) is much more suitable for direct pitching.

[a10t2]

Keep in mind that 2 month old yeast is only 60% viable.

Not very likely unless it was mishandled, but of course one of the reasons to make a starter in the first place is to check on yeast vitality (which is why the Wyeast packs are so nice).

[Big Monk]

Keep in mind that 2 month old yeast is only 60% viable.

Not very likely unless it was mishandled, but of course one of the reasons to make a starter in the first place is to check on yeast vitality (which is why the Wyeast packs are so nice).

You're right. I'm being very conservative because I am assuming that BeerSmith is being conservative as well. I don't think that it is a stretch to say that BS is assuming worst case viability based on a 20% p/month factor.

[Richard]

BeerSmith uses a 21%/month default aging rate for liquid yeast, but uses 10%/month for White Labs yeast in the PurePak packaging. Brad has confirmed that this reduced aging rate is based on experimental viability numbers provided by White Labs: http://www.beersmith.com/forum/index.php/topic,16893.msg63846.html#msg63846

[Big Monk]

BeerSmith uses a 21%/month default aging rate for liquid yeast, but uses 10%/month for White Labs yeast in the PurePak packaging. Brad has confirmed that this reduced aging rate is based on experimental viability numbers provided by White Labs: http://www.beersmith.com/forum/index.php/topic,16893.msg63846.html#msg63846

With this in mind:

1 pack at 75% (WL guarantees 95% off the line) viability is 90 B cells. So our estimate given 1.00 M/ml/°P, 12 °P, and 18.93 liters was 227 B cells required would be satisfied with ~ 2.5 packs.

So pitching one pack would be:

( 120 * 0.75 ) = 90 B cells -> ( 90 / 12 ) / 18.93 = ~0.40 M/ml/°P

Go with that starter!