Rhino farts only when reusing yeast

[gobsh]

I currently have extreme rhino farts in two separate batches. Both used washed yeast from the same original batch, which took a new pack of S-05. The first batch had no rhino farts.

Seems weird that the yeast could have mutated and started misbehaving so soon. This is only 2nd generation.

Any thoughts, please be kind enough to drop them in here!

 

[dgr]

Dry yeast contains more than yeast. Try using some yeast nutrient and energizer next time you use washed yeast.

If this was a wine, I would recommend you aerate it. I don't know what to do about a beer other than hope the aroma doesn't linger in the final product. Mmmmm Brimstone Ale.

 

[snowveil]

Yeast will change from generation to generation. By reusing yeast you're essentially selecting certain characteristics of the yeast whether you know (or intend) it or not. It might not necessarily be a mutation, but maybe the more flocculant cells produce higher levels of sulphur. As long as it's off-gassing, I wouldn't really worry about it anyway.

Out of curiosity, what type of beer was the original batch from which the yeast was washed?

 

[gobsh]

They are all similar IPAs below 1.065 SG.

1st batch fine, good fermentation and no farts.
2nd heavy farts but I blamed it on some ginger root I threw into the boil. Yeast came from washed cake when racking to secondary.
3rd same smell. Yeast siphoned from bottom of secondary and grown in a stirplate starter.

I always use plenty of nutrient. Never had an infection.

I would use a fresh pack each time but I live in a country where you can't get it and shipping is expensive, plus in summer the yeast would die in hot conditions on its way to me.

 

[CoTron]

My guess is that by reusing the yeast you had a bigger, healthier amount of yeast than the first time you used the yeast. Maybe that led to a faster, more aggressive fermentation which could be producing the same type of smells as a slower fermentation but just making them much greater quantities.

 

[gobsh]

So the yeast is either extra sick or extra healthy!

Another thing is that it seems to clump together a lot more. I can see pea-sized bits of it flying around inside the fermenter.

I will report on flavours.

 

[gobsh]

9 days after the OP and both batches still stink. One has been racked, the other still in primary. No difference between the two.

 

[gobsh]

Over a month now some brewing and I've bottled one of the problem batches while the other is still soaking up some tangerine peel in secondary.

Fart smell almost gone from both but the batch I bottled had a weird metallic taste to it, like sucking on an empty spoon!

Hopefully they will start to behave themselves after a while in the bottle

 

[tooldudetool]

Typically rhino farts come from stressed yeast, either not enough nutrients or not enough dissolved oxygen. I brew the occasional hard cider, and the last few times the house stunk like a fart factory. I used the Wyeast beer nutrient before pitching the yeast, but it didn't seem to help. This last time I added DAP yeast nutrient about 24 hours after pitching when it was stinking to high hell, and amazingly the sulfur smell stopped coming out of the airlock within an hour and never returned. I know you said you use plenty of nutrient, so that probably isn't your issue. Are you oxygenating well enough for a large repitch? I've also heard that it's not recommended to reuse yeast from dry hopped IPA's just because the hop oils can coat the yeast and make it not as suitable for repitching, maybe that has something to do with it. I use S-05 all the time and haven't gotten sulfur notes before.

 

[gobsh]

Both the beers are long in the bottle now and although the fart smell has gone there are still some off flavours I'm not happy with. I have resolved never to re-use yeast unless it's my only option!

 

[gobsh]

Long time since I actually logged in to this place rather than lurking, so here's an update on the re-used yeast problem.

Never got to the bottom of it and was never happy with the beers it produced. Some off flavours that I've never had before or since, which never really went away.

I've never re-used a yeast cake since then as a precaution, which is a shame because yeast is really a rare commodity where I live. Worth the spend, I suppose...

 

[Beerbeque]

I'll bet your problem is a house "bug" just like I got in my brewery. Re-using yeast greatly multiplies the house bugs that all breweries have. I had to dump all my slurries, start fresh with new yeast, replace my bottling bucket and hoses. I also scrubbed each and every bottle with cleaner and hot water before refilling. oh, and fresh Starsan solution mixed with distilled water on everything the beer gets near. It worked for me and my latest batches taste clean and don't give me gastro problems.

 

[gobsh]

Sounds like your problem was much worse than mine, beerbeque. Well done on getting rid of it.

I could have made it clearer in my previous post but I'm positive it wasn't an infection problem, just weak yeast. The off flavours only came out of the two batches which re-used the original yeast. No other batches brewed in the same period had this problem. I used new yeast packets on the other batches.

I stopped re-using yeast and the problem went away. Most likely I didn't re-use 'properly', but I decided that re-using was not worth this risk, and I haven't had the problem since.

Further input welcome, of course!

 

[DurtyChemist]

First, selecting yeast from the secondary are probably the least flocculant so this could contribute to part of the problem.

Second, consider using liquid yeast.

Lastly, and I know it's debated here, make a starter that's 1/2L larger than normal. Before you pitch the starter yeast on the wort swirl it up and save the extra 1/2L in a sanatized container. Use this saved yeast for your next batch and crest a starter the same was I just described and repeat. It might help.

 

[gobsh]

First, selecting yeast from the secondary are probably the least flocculant so this could contribute to part of the problem.

Second, consider using liquid yeast.

Lastly, and I know it's debated here, make a starter that's 1/2L larger than normal. Before you pitch the starter yeast on the wort swirl it up and save the extra 1/2L in a sanatized container. Use this saved yeast for your next batch and crest a starter the same was I just described and repeat. It might help.

Sorry if I didn't make it clear... I took the yeast cake from the bottom of the primary of the original batch after racking the good stuff to secondary. Maybe I just got the tired and dead yeast rather than the healthy cells that were still floating.

Is the starter thing debated because people prefer not to throw the 'beer' of the starter into the fermenter because of its nastiness? I haven't read much on the topic on here. I discard it personally because, well, it's nasty.

I have been making stir starters since this bad couple of batches as it happens and I've had some ferocious fermentations hehe. Good investment, that stir plate.