Burnt creamed corn smell in yeast starter

[blitzd]

I posted this in the beginner forum but it probably belongs here:

I have a yeast starter that I've been stepping up from some Hennepin dregs. The first two steps went good, and I have a nice thick layer of yeast at the bottom after the third - but it smells of burnt creamed corn now. It most certainly did not have this smell after the first two steps.

Starters were all done with DME for 24 hour periods. I went from 600mL @ 1.020 to 1.2 L @ 1.035 to 1.75 L @ 1.040. At the end of the last step I let it rest for about 6 hours and then cold crashed it, I didn't notice the smell until this morning when I went to decant it. I was going to use it later today, but now I'm not so sure.

... Sorry for the double post.

 

[grimzella]

I tried this same thing with troise pistoles 4 bottles of dregs. my second round smelled sour/nasty. so I chucked it. everything was infection free as far as I know.. I took great care not to contaminate anything during this process. This was my first attempt at this.

 

[blitzd]

Hmmm, I have read up a bit more since I posted that and it's apparently not uncommon to have sour or nasty tasting starters. I can't find too much on the burnt creamed corn smell I have though. So far as I can tell it's likely either from DMS - but I used non-pilsen DME for my starter wort, or it's from dead yeast. I did run the third step a bit hot at 85f (dunno why that seemed the appropriate temp when I set it), so maybe I killed it.

I'm going to run another starter through so that I can taste the decanted beer and see if it actually has that taste to it.

 

[grimzella]

I wouldn't think you killed anything at that temp. I was thinking of washing the dregs first instead of just dumping them into my starter.

 

[blitzd]

This is also my first time doing up a starter from dregs, so it's a bit of an experiment. I think I'm just going to go with it this time around, in the name of brew science!! I'll collect some more yeast while this batch is brewing and see if it turns out any different as well.

If you really want the Trois Pistoles yeast, they apparently use this http://www.wyeastlab.com/rw_yeaststrain_detail.cfm?ID=67. I love Trois Pistoles and La Fin du Monde...

 

[insanim8er]

When you cover it, you you don't burn off the DMS. This gives off flavors and aroma of corn like you describe. And after I wrote this, I see you mentioned it... But ya.

 

[blitzd]

When you cover it, you you don't burn off the DMS. This gives off flavors and aroma of corn like you describe. And after I wrote this, I see you mentioned it... But ya.

All my starters were entirely uncovered for a 15 min boil, using light DME (Briess I believe). I only cover them when they're cooling, generally in an ice/cold-water bath.

I'm wondering, if it is DMS in the starter if such a small amount would affect the flavour/aroma of the beer the yeast is used in? Guess I'll find out soon enough!

 

[blitzd]

My starter turned out to be a thick layer of trub instead of yeast! The upside - I now know the difference between trub and yeast!

Second attempt I ended up with some definite yeast, smelled a bit of acetic acid, but I went ahead and used it anyway - my wort ended up going moldy sitting waiting for a week in the fridge, so I racked it out into a different fermentor, pitched the nail polish remover, and now it's a science experiment! It's fermented for 3 weeks @ 75f (ramped up from 68f the first week) and gone from 1.064 to 1.001. There's .75oz of dried/fresh ginger in the wort, so it's hard to say if it actually tastes any good at this point. I'm going to leave it in secondary for another month and see how things turn out - I'm not holding out any hope for it being drinkable though, it's been a bit of a disaster. I'm going to stick to bought yeast for the foreseeable future I think

 

[tgmartin000]

mmmmmmmm.....Hennepin. Great, great beer.

I recently bottle harvested my first yeast - Conan. All 3 steps smelled horrible. I was worried, but pitched it into a $60 wort anyways. Turned out great! I don't worry too much about how my starter smells after that.

 

[blitzd]

Just checking back in. The yeast for this did indeed ferment like nobody's business, despite all I put it through, but I was way off on the amount of ginger (.5 oz dried, .25 fresh per 6 gal), and it overpowers everything even after a month and a half. It's not bad when mixed 50/50 with another belgian pale ale I did though.

 

[LesIsMore]

Did you ever find anything out with the creamed corn smell? I just ran into the same problem trying to harvest dregs from Hennepin as well. DMS was the first thing that came to my mind with the corn smell, but it doesn't seem that DMS is a concern with dme. In How to Brew, he mentions a possible bacteria infection, but that would have more of a rancid, cooked cabbage character.

Anyone else have any thoughts? I'm still trying to figure out where the smell came from and if I should give the starter a shot since I'll be decanting the wort.

 

[ACbrewer]

I don't think you can get DMS if using LME/DME. DMS forms when trapping the Sulfar during the boil. Since DME is dried LME, and LME uses a LOT of boiling to reduce from wort to extract, and with that boil being open... Anyhow I think extract generally avoids the DMS problem.

I haven't got a clue on the starters cream corn problem tho