[HopDen]

FWIW, on my Kolsch recipe, I start ferment at 60* for 2 days then lower to 55* until I get about 10 points away from FG. Then I let the temp free rise to 68*, set temp controller, where it will finish out and FG is steady for 3 days. Cold crash at 35* and let it sit at that temp for at least 10-14 days. I like the slight fruity taste I get from 68* Maybe I don't need a diacetyl but the process works for me. 

[Robert]

FWIW, on my Kolsch recipe, I start ferment at 60* for 2 days then lower to 55* until I get about 10 points away from FG. Then I let the temp free rise to 68*, set temp controller, where it will finish out and FG is steady for 3 days. Cold crash at 35* and let it sit at that temp for at least 10-14 days. I like the slight fruity taste I get from 68* Just my method and it works for me.

If you're raising the temperature to 68°F at that late point, the yeast are no longer producing flavor compounds but reducing them, so that's not where you're getting fruitiness.  If 60°F is on the warm end for your yeast, that critical first two days is probably giving you the fruit.  But as you say the whole program gets the result you like, so that's what  counts.

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[HopDen]

FWIW, on my Kolsch recipe, I start ferment at 60* for 2 days then lower to 55* until I get about 10 points away from FG. Then I let the temp free rise to 68*, set temp controller, where it will finish out and FG is steady for 3 days. Cold crash at 35* and let it sit at that temp for at least 10-14 days. I like the slight fruity taste I get from 68* Just my method and it works for me.

If you're raising the temperature to 68°F at that late point, the yeast are no longer producing flavor compounds but reducing them, so that's not where you're getting fruitiness.  If 60°F is on the warm end for your yeast, that critical first two days is probably giving you the fruit.  But as you say the whole program gets the result you like, so that's what  counts.

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Robert,
I use WLP029. Temp range is stated as 65*-69*
I don't know enough about yeast/fermentation in regards to the flavor compounds to formulate a argument for it.
So, with my fermentation schedule as posted for this yeast, at what degree of attenuation do you propose a boost in temp?
White labs states that 50% attenuation happens within 30 hours. I'll have to reference my notes and see if thats the case with my process because that seems entirely to fast.

As always, thank you for the input.

[Robert]

If what you're doing works, I'd say keep doing it.  But in general, fermentation schedules are planned around either a rising or steady temperature  rather than lowering it in the middle.  The concern is that lowering the temperature prematurely will shut down the yeast to some degree, and I'm not sure what it would be intended to do.   If you want a flavor profile characteristic of either warm or cool (for the strain) fermentation,  that is, fruitier or cleaner, the early stages are where that will be influenced.   But again, it's all about what works for you.  You could try a batch starting at the lowest temperature you find acceptable and let the temperature rise to 68° after the 2/3 of the way, or ~50% AA, I've mentioned, and see if it's any different,  or more or less convenient.  If nothing else, it's less complicated.

On a side note, the genomic research has shown 029 is an English yeast in the Whitbread B family.  In that context, 30 hours to 50% sounds about right.  Probably for most ale yeast.  But I'm not sure what conditions they used to determine that. (If fermentation data for a given strain don't include fermentation temperature I'd default to assuming they use the high end,  maybe 68°, so that the analyses of fermentation products are worst case values.)

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