Banana esters from Safale S-04

[hurleyci]

So we brewed a porter on Saturday on our new all grain set up, massively underestimating our efficiency! We ended up with 30 litres of 1.077 wort. We had a starter made up of S-04, which we've been using for any Irish/British styles so far. I pitched it on Saturday night, sealed it up and went to bed. Woke up yesterday to find the fermenter lid blown and my beer oozing all over the place! So, put on a bigger blow off tube, moved it outside, cleaned up and it just kept hapening. After a few hours it subsided to the point that the large blow off tube was able to keep the lid closed at least!

I didn't think to check the bucket thermometer when it was in the house, but the heat was off and the ambient temp was 16 degrees when I came down in the morning. In the garage the bucket temp yesterday evening was 22, absolutely roasting! I took a gravity reading last night and it's down to about 1.03 but the smell and taste of bananas is pretty present!

This isn't the first time I've had this happen with this yeast. Our Irish red a while back had the same smell, filling the room with the banana-y gas!

I'm kinda just curious about other peoples experiences with this yeast. I'm aware that 22 is too high and if we use it again we will take steps to get it lower. The banana seemed to fade with time in our Irish red and we planned on aging this porter til August anyway. Can people verify that esters die down or have I imagined this?!

The yeast is a beast, that's for sure, it starts up within hours and just demolishes a beer within days!

[Ciaran]

I'm guessing since the number of cells per gram is higher in dry yeast than liquid might be why you are getting the lid blowing off.  I don't think its recommended to make starters with dry yeast, something to do with depleting their reserves.  I've also recently had a kolsch brew which had strong banana aroma which eventually faded off within a 4-5 weeks in the bottle (it was a wyeast german ale strain with no fridge for temp control).