Are off flavors created during the lag phase?

[Burquebrewer]

I've been trying research this and I am not coming up with a clear answer. If yeast (say S-05) is pitched high (say 85F) but the wort is chilled quickly to 68F before the lag phase is over, then the beer fermented in the mod 60's, will there be off flavors from pitching hot? Or do the off flavors start to form after the lag phase?

Thanks.

 

[jjeffers09]

It depends what "off" flavors you're talking about. Some fermentation flavors have precursor acids and compound already developed in your wort, during the lag phase they are acclimatized to the wort and fermentation conditions. While nothing about yeast is set in stone, and I can't say if S-05 will or will not have the expected results. The factors are in the wort, the mashing conditions, the water chemistry, the O2 etc. If sterols, amino acids, peptides, other proteins, and fatty acids can be biosynthesized during this phase will positively show in the log phase. With strong fermentation. I am not sure what exactly you want to see in this because it is not clear. If any yeast is pitched at 85F then chilled quickly to 68F within the 3-15hrs of pitching and the pitchrate makes a difference too. I think you will not have a "clean" fermentation characters from that batch, but that is just my hypothesis.

 

[brick_haus]

Yes, for a variety of reasons, off flavors will occur when you pitch warm. But way more detailed info is necessary to know what you should expect.
Next time just be sure to pitch closer to fermentation temp (yeast and wort). Yeast would rather warm up to wort temp a little than cool down to it, so ideally your yeast should be a bit cooler or equal to the wort temp. Learn as much about yeast and how it works to improve your beer. Sometimes proper yeast handling is what will make good beer great.

 

[Burquebrewer]

I guess I was looking more for a general answer to the question rather than a case specific one. I've read many conflicting reports about the topic...some saying that there are no byproducts being made during the lag phase, therefore no (or very little) risk in off-flavors as long as the temp is optimal when the fermentation begins after the lag phase. Others state that pitching too warm causes fusels and diacetyl production right away?

 

[jjeffers09]

off flavors start in your mashing water and grains. I believe the yeast fermentation process then "brings them to light" in the final product. Some lipids and acid absorbed by the yeast during the lag phase will be "biosynthesized" or crapped out into the beer during Log phase. That is I believe the process of obtaining, ending up with, esters and phenols in your beer.

 

[brick_haus]

I guess I was looking more for a general answer to the question rather than a case specific one. I've read many conflicting reports about the topic...some saying that there are no byproducts being made during the lag phase, therefore no (or very little) risk in off-flavors as long as the temp is optimal when the fermentation begins after the lag phase. Others state that pitching too warm causes fusels and diacetyl production right away?

I agree with what you have read. But TIME, which was not mentioned, is a factor. As you may already know, lag time is the best opportunity for bacteria to form/grow, so the shorter lag time the better. And the happier the yeast is, the shorter the lag time (to an extent). Pitching warm isn't conducive to happy yeast.

 

[m1k3]

In the Brulosophy warm pitch experiment they exceeded the "ideal" ferm temp by 6F for 4 hours.

The 85F you proposed pitching is 13.4F over US-05s max ideal ferm temp of 71.6F.

Before I had good temp control I would pitch warm thinking the wort would cool before fermentation would take off, only to have huge blow off. If you can truly chill rapidly... I'd do that before pitching. At least get down to 77F, the maximum recommended temperature for US-05.

My recommendations would still stay the same with other yeasts (but the recommended temperature vary by strain).

As far as off flavors, the most likely result of pitching warm is more esters. Not that esters are the same as what most people consider to be off flavors (infection, acetaldehyde, fusel hot alcolhol).

 

[jjeffers09]

those are ideal temperatures are for inoculation and flavor, not what yeast does the most work. For instance a Lager yeast will bud and have a "stronger" log phase at ale temperatures, but for the right lager flavor are fermented cooler. I believe almost ANY yeast will have a more rapid reproduction in an ideal nutritious wort at 85-95F vs 65-75F. This question started out with the OP letting his conical chill in the sun, and it raised his wort to 85F and had to move it and chill back to ideal temps. Within the short timeframe you won't see anything within that window of, lets call it a, temperature slip to effect the flavors. The yeast are only acclimating to the wort at that point and are starting to pull in nutrients some (lag)3-15hrs later before moving into munching on some sugars(lag).

Just like thanksgiving, you don't walk right in, sit at a plate with a knife and fork ready, and just dive in. You mingle and say your hellos, when everyone decides they are ready to eat you all sit down together and feast.

 

[Burquebrewer]

A bit late, but thanks JJeffers. The beer came out pretty good. I've learned from my mistake (that's what mistakes are for, right?)