How warm is too warm for Wyeast 1728?

I made an AG batch of Karl’s 90/- (see: … nety90.pdf ) over the weekend, and pitched a well-made starter of Wyeast 1728 into it. Fermentation was controlled using a temp controller with a probe inside of a thermowell.

The temperature setpoint was 18.0 C (~64 F) with a differential of 1.5 C, meaning it rose as high as 19.5 C (~ 67F) before the refrigerator would kick on and cool it down. I peeked in on it this morning and detected an aroma I hadn’t expected, and was searching online for whether this yeast offgases anything unusual when I read that the recommended temp for 1728 was 60F, and that pushing 70 F produces unwanted fruity esters. I suppose I’ll find out eventually, but I’d appreciate anyone’s insights if they know: will I get “unwanted fruity esters” from temps between 64-67 F?

Also, if anyone knows the answer as to whether this yeast offgases any unusual smells, that’d be cool, too… I never found the answer, in my searching.

Cheers. :cheers:

I fermented it in the lower 70s without problem. It gave some fruity esters, but they faded quickly. I used this in Winter Warmer two years ago.

I’ve only used that yeast once with good results. I try to keep the fermentation temps in the lower range of what Wyeast recommends to avoid the esters.

In this case the range is 55°F - 75°F. Personally I’d keep this one under 65.

I’m actually making a variation on the Winter Warmer this weekend with this yeast.

If your thermowell is in the fermenting beer, I would switch the thermostat to degF and use a 1 deg differential.

Well, I can’t do the former; celsius only. But I switched it to a 0.5 deg differential.