I haven't made too many lagers, but this winter I'm trying to make some German Lagers in my basement (Norman Bates room) that is a steady 48. My last two have had diacetyl. My first was a Dunkel with WY 2206 that I added some US 05 to and it turned out fine. My last one (Vienna Lager) with WY 2308 I even did a diacetyl rest for two days then back to cold for awile and I figured that should do it and I carbed it. Next, I taste a sample and there is diacetyl in the aroma and flavor so I warm it up again. The buttery aroma and flavor are still there. I really don't want to dump this before I've tried everything. Does diacetyl vanish over time or should I add more yeast? Also, I have a Doppelbock fermenting on the 2308 slurry and I want to avoid the "butter". Suggestions please.