I am on all grain brew #47 so no expert, but not a novice either. I brewed my first Kellerbier at the weekend and pitched a starter of White Labs - Old Bavarian Lager Yeast WLP920 (liquid yeast, in date, kept in the fridge). Fermentation took a day or so to get going and I can't keep the temperature down as sod's law we are having a warm spell of weather here in the UK, unusually! It's at roughly 16 deg C rather than 12 deg C. Anyway, as I get close to the FV, I get this distinct smell which I have not experienced before, and it is definitely coming from the airlock. It isn't quite like rotten eggs, but it certainly not pleasant. Is this what some yeasts smell like? Or is this a sure sign of an infection and I should dump the lot? Thanks for any helkp/advice.