Oxygen in lager yeast fermentation

[Aloha_Brew]

I had recently made a Vienna and an Oktoberfest with some White Labs Oktoberfest lager yeast, just to compare any difference in taste profile. Unfortunately, I was still learning about yeast and thought nothing of the following experiment: pitching 1 vial into the Vienna and a 1 liter starter from another vial into the Oktoberfest. I noticed a distinct sulfur taste even after lagering at 40 degrees for 4 weeks in the Vienna, while the Oktoberfest tasted overly sweet. So, it got me thinking...has anyone tried adding oxygen to a primary versus creating a starter to compare results?

Not sure it was so distinctly different, but I've found in two batches so far that underpitching a lager definitely produces a sulfur taste profile that is very hard to eliminate, even with a higher temperature rest to thin out potential to thin out acetaldehyde. Just wondering if maybe overpitching might have been my problem with such a sweet taste profile in the Oktoberfest.

 

[bja]

has anyone tried adding oxygen to a primary versus creating a starter to compare results?

You should be doing both, especially with a lager.

Just wondering if maybe overpitching might have been my problem with such a sweet taste profile in the Oktoberfest.

You severely under pitched both of them.

 

[KeystoneHomebrew]

Unfortunately you did under pitch both. There's a many tricks and pitfalls with lagers. But just some of my easy to do processes.

I put the beer into the fermenter and then cool it to fermentation temp (usually over night)
I aerate right before I'm going to pitch the yeast, so not on brew day as typical
My minimum amount of yeast for a lager is 3 packages, for every 10 points above 1.050, I add another pack. I usually use more (or make a very big starter)
When I transfer to secondary for the lagering stage, I suck up a tiny amount of yeast from the fermenter to help finish cleaning up any by products.

 

[Aloha_Brew]

Unfortunately you did under pitch both. There's a many tricks and pitfalls with lagers. But just some of my easy to do processes.

I put the beer into the fermenter and then cool it to fermentation temp (usually over night)
I aerate right before I'm going to pitch the yeast, so not on brew day as typical
My minimum amount of yeast for a lager is 3 packages, for every 10 points above 1.050, I add another pack. I usually use more (or make a very big starter)
When I transfer to secondary for the lagering stage, I suck up a tiny amount of yeast from the fermenter to help finish cleaning up any by products.

In reading Chris White's Yeast book I noticed that a 1.5l starter is the best size for one vial (1.3 ounce equivalent = about 100 billion cells) for propogation. So, if I make a 2-3l starter and aerate it (which they did not) after adding 2 vials then I should have more than enough cells. However, this does not really explain the sweetness I tasted in the profile. I guess it could be diacetyl, but I'm not 100% on that, that's why I'm trying to rule out pitching amounts.

 

[KeystoneHomebrew]

A 2-3L starter should do the trick, assuming you started with 100 billion cells. A vial of White Labs yeast averages around 70 billion. Post the Oktoberfest recipe and its FG if you don't mind.

 

[Aloha_Brew]

Had the following:
76% Vienna
16% Munich
8% Crystal 80
.5 oz Magnum hops for bittering

OG was about 1.050 and FG was about 1.010.