A good rule is to initiate the diacetyl rest when you have half of the original specific gravity points remaining. For example, when starting with 1.048 then initiate a diacetyl rest at 48/2 =24 or 1.024. Increase the temperature to about 16-18C and allow the fermentation to complete at this elevated temperature.
I disagree, has to be 61s.
That’s actually what I do. I’m usually under pressure and want to spund so I do this to make sure I don’t lose free co2 and to take care of the diacetyl as well.
As I’d mentioned, when the curve starts to flatten, increase temps by 6-12F. Once the curve is flat, leave it 3-5 days more to let the yeasties finish the job. They are done with Ethanol, but still on the job for diacetyl.
I think I am close to the starting point for diacetyl rest. Do you agree ? OG=1,057 presentG=1.0285. Even though the Float device is not very accurate.
I was listening to a recent episode of the Experimental Brewing podcast and Denny mentioned that oxygenation is needed for liquid yeasts to build up sterols. (Sterols help keep the cell wall flexible, which allows them to bud more easily). However, dry yeast manufacturers stop the yeast's growth while it is in the sterol production phase. So, there are lots of sterols and therefore there is no need to aerate.
Thanks for the explanation. It's an interesting point that will save my time and prevent contamination.
