Potential Effect of Long Lag Time??

Up until this last batch, I always just pitched a vial of the appropriate White Labs into the wort. Lag time is usually about 15 hours or so. I had some old yeast that was approching it's expiration date, so this time I made a starter(750ML h2o and 1/2 cup of DME). After about 15 hours or so, the starter showed little signs of fermentation. I thought that I might have missed it during the night and could not measure gravity since I had broken my hydrometer the day before. I went ahead and added a little more DME, re-agitated and watched it carefully. A few bubbles through the airlock, but never any krausen. The next day I pitched it anyway and went away on business. SWMBO said it took about 36 hours for the fementation to become active enough to require a blow off tube. After all of this lagtime and such, What kind of off flavors can I expect??? Why such a long lag time with a starter? Temps were correct and I used the same method of aeration that has been successful on all of my other batches.

As long as your sanitization was good, I'd say you'll be fine. Too long a lag increases the risk of contamination, but in my experience, things have to go really wrong to have an effect. Relax, have a home brew.

Starters don't always show signs of fermentation as that means they have shifted out of the growth phase. Starters that are still growing when you pitch them is ideal. The extra lag time shouldn't make any difference at all. 36 hours isn't a big deal & blowoffs mean lots of happy yeast.

david_42 said:

Starters don't always show signs of fermentation as that means they have shifted out of the growth phase. Starters that are still growing when you pitch them is ideal.

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Thats good. What are the signs of success when making a starter (aside from gravity)? I have read that long lag times can lead to "vegetable" flavors in the finished product. How much lag time are we talking here??

ScoutMan said:

Thats good. What are the signs of success when making a starter (aside from gravity)? I have read that long lag times can lead to "vegetable" flavors in the finished product. How much lag time are we talking here??

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I was under the impression that "vegetable" flavours were caused by DMS (ie boiling with the lid on.) Kind of a cooked cabbage flavor.

Thats true also. Vegetable flavors can also be a result of a bacterial contamination that occurs in between the time you pitch and the time you have active fermentation(lag time). Once active fermentation begins, your beer is somewhat protected by the layer of gas in the headspace of the fermenting vessel. Or at least that's the way I read it.

Pabst Blue Robot said:

I was under the impression that "vegetable" flavours were caused by DMS (ie boiling with the lid on.) Kind of a cooked cabbage flavor.

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i still new well not that green but i was never told that cooking with the lid on would casue off flavors in the beer. i normally cook with the lid to make sure nothing falls in. however im always checking for boil overs. so tell me is this bad and should i stop boiling with a lid???

per Mr. Palmer.........
Chapter 21 - Is My Beer Ruined?


Dimethyl Sulfides (DMS)/ Cooked Vegetable Flavors
Like diacetyl in ales, DMS is common in many light lagers and is considered to be part of the character. DMS is produced in the wort during the boil by the reduction of another compound, S-methyl-methionine (SMM), which is itself produced during malting. When a malt is roasted or toasted, the SMM is reduced beforehand and does not manifest as DMS in the wort, which explains why it is more prevalent in pale lagers. In other styles, DMS is a common off-flavor, and can be caused by poor brewing practices or bacterial infections.

DMS is continuously produced in the wort while it is hot and is usually removed by vaporization during the boil. If the wort is cooled slowly these compounds will not be removed from the wort and will dissolve back in. Thus it is important to not completely cover the brewpot during the boil or allow condensate to drip back into the pot from the lid. The wort should also be cooled quickly after the boil, either by immersing in an ice bath or using a wort chiller.

When caused by bacterial infection, DMS has a more rancid character, more liked cooked cabbage than corn. It is usually the result of poor sanitation. Repitching the yeast from an infected batch of beer will perpetuate the problem.