diacetyl rest

[Taff1972]

This is my first blog and my first all-grain brew any help would be much appreciated.
I'm not sure about the sequence of diacetyl rest, do I rack before I raise temperature for to days and do I raise it gradually ,or do I rack after cold crash or before ???
I'm brewing a BJCP 1B munich helles
White Labs WLP830 yeast

 

[microbusbrewery]

Do the diacetyl rest towards the end of primary fermentation, before racking off the yeast or cold crashing. I usually do it when I'm about 80% there to my expected final gravity. You do it so the yeast can clean up the byproducts from fermentation, so you want all the yeast in there so they can do it as quickly and efficiently as possible (reason not to cold crash). I let mine free-rise for the diacetyl rest, so the temp increases fairly gradually. When dropping temps after the rest, I do it slowly over the period of a week. Jamil recently talked about if you drop the temps too quickly, it can trigger the yeast to expel a bunch of byproducts.

 

[dmtaylor]

Don't rack it! Leave it on the yeast. In fact I purposely swirl the yeast back into suspension once every couple of days to ensure decent contact with the yeast. You want to do the diacetyl rest when the specific gravity is about half of what you started. So for example, with OG=1.050, start the diacetyl rest when the gravity falls to 1.025 or even a little lower 1.022 or whatever is fine. If gravity is much lower than half of OG, you won't get all the advantages of it.

FWIW, I am fermenting two Marzens right now with the same yeast. I brewed last Sunday, and I began the diacetyl rest after just 5 days on Friday. It still seems to be fermenting very vary slowly even though the gravity is like 1.011 on both, so I think I will wait until Wednesday or so to bring the temperature down, after fermentation is definitely complete, then add gelatin and should be able to bottle by the weekend or if not then middle of next week. Gelatin is your friend, but don't add it until fermentation is all done. Then you can skip lagering altogether if you want, as an experiment if nothing else, that's what I'm doing.

 

[Taff1972]

Thanks guys