Buttery Taste Lager

i am fermenting my first lager. primary temp 48 f. Yeast is S-23. I am close to my FG of 1.015.

The beer has a definite buttery taste which I assume might be diacetyl. will it disappear during Lagering? Can I do anything like change temperature before lagering? Or am I just stuck with this flavor?

Do a diacetyl rest. Bring it to room temps now while the yeast is still going.

Don't have to bring it to room temps. Just slowly bring it up about 10 degrees F over the next day or two, and leave it there for a week before you start cooling it down again for lagering.

i would suggest ramping up to 65 degrees for 24-48 hrs... then transfer to a secondary to lager in and ramp the temp down slowly over a week or so to your lager temp.

It's a good time for a diacetyl rest- I usually do one when the lager is at about 1.020. Bring the temperature up at least 10 degrees, and let it stay there until fermentation is finished and the buttery flavor is gone. It may take more than 48 hours to clean up all of the diacetyl. Diacetyl in large amounts tastes buttery, but in small amounts it presents as an oily mouthfeel or a slickness on the tongue. You want that completely gone before racking and lagering!

It will get worse during lagering, not better, so it's time to get rid of it now!