Will yeast clean up diacetyl post-fermentation?

[neb_brewer]

I've done a lot of reading and I'm still not clear on the diacetyl rest. My last 3 lagers I've done the d-rest when fermentation starts to slow or the gravity is about 75% to terminal. Is this necessary though? Could I let the yeast ferment completely to its FG and THEN do the diacetyl rest? Would the yeast clean up after themselves at that point?

This question is also applicable for people who may completely miss the end of fermentation where they could have brought the temp up. Would a longer d-rest work to clean up the diacetyl for these situations?

What about if I pitch the yeast at ferm temps? There should be less diacetyl created using this method. Would a 24-48 hour d-rest post fermentation clean up any diacetyl remaining? Is a d-rest even necessary in this situation?

I just don't like having to raise the yeast to temps they don't like and rushing them. If I can let them do their thing until FG, then do the diactly rest for 24-48 things would be easier for me.

 

[theredben]

Nope, not if they are truly done fermenting and have flocculated out of suspension. If you were to raise temps right when FG was reached, then it might happen, but not after. That is why it is recommended to D-rest at 75%, not like 95%. It is cheap insurance.

Most of the flavour profile is created in the first few days anyways, so it is not really a big deal for the yeast to chew through the last few SG points at a higher temp.

 

[neb_brewer]

Is a d-rest necessary if you pitch your starter when both it and the wort are at ferm temp?

 

[theredben]

Depends on the yeast, some produce lots of diacetyl. Until you have used the same lager yeast a few times, it seems like cheap insurance to perform a D-rest just in case.