Harvested yeast starter...a little sour

[AbeM]

My first attempt at harvesting yeast from a commercial beer (a can of Heady). Starsan on everything, boiled all my step ups for 5 mins, thought I was doing everything right...and the yeast is growing. Was stepping up last time this morning, and tasted a little of the decanted spent wort.

It was a little sour. Not a lot sour, but definitely sour.

Does this mean I messed up the sanitation, dump it; or is there some logical reason that the wort would have a slightly sour taste due to the higher concentration of yeast or something something, maybe, please?

 

[cshamilton]

Unless you hop your starter wort, it will often taste a bit sour. As long as you can grow up a healthy starter you should be fine. There is always a risk when harvesting, I've never done heady but I've harvested Bell's yeast. The starter had a slight twang, but the beer turned out awesome with no trace of contamination.

 

[quijiba]

My first attempt at harvesting yeast from a commercial beer (a can of Heady). Starsan on everything, boiled all my step ups for 5 mins, thought I was doing everything right...and the yeast is growing. Was stepping up last time this morning, and tasted a little of the decanted spent wort.

It was a little sour. Not a lot sour, but definitely sour.

Does this mean I messed up the sanitation, dump it; or is there some logical reason that the wort would have a slightly sour taste due to the higher concentration of yeast or something something, maybe, please?

Could potentially be an infection. I've never had sour from my step ups. I would still recommend making a beer with it to see how it turns out though. Might end up with a fun fruity ester profile that comes off a little tart. I would give it a go as long as it still tastes good from your starter right now!

 

[AbeM]

Well I will give it a go. Hate the thought of potentially dumping 5 gallons of beer (though I have done it once with a truly awful pumpkin ale I once brewed). There was certainly no pellicle or off smells coming from the starter, so here's hoping after a week in the fermenter that the yeast drops out and takes the sour taste with it.

 

[Dcpcooks]

Starter wort tastes like crap! It's not indicative of your finished beers profile. If your sanitation was solid run with it. Next time flame the can opening with a lighter or propane torch. You can also flame the flask to insure you've killed everything before you transfer the wort. Just a quick pass waive the flame over and around the top. That's common practice in a yeast lab for sterilization of gear.

 

[AbeM]

So my final step up is 1500 ml at 1.040. My intent when this stops fermenting in a few days is to just swirl the whole thing up and pour out six half-pint (heavily sanitized) mason jars. Then, a few days before my next brew, prepare a liter starter and dump one of these in. I've never done this before, does the approach sound like it should work?

 

[Dcpcooks]

Yes just get some distilled water or boil some and cool it. Then you can crash and decant the spent wort. Add the new water and swirl it up. You'll have to calculate how much yeast you made and figure out what you can save for the next pitch. But it's totally doable.