Twin Yeast Starters Quite Different

[XPLSV]

Had a surprise with some Burton Ale yeast starters this past week. Used the White Labs WLP023 Burton Ale Yeast in the new packets. I planned to do two back to back batches, so I made two separate yeast starters. Prepared each exactly the same, using the same techniques I have used for the past 5 plus years. This is the first time I used the new White Labs packaging and had a bit of a challenge getting all the yeast out of the packet for the first one...it had clumped quite a bit into the bottom of the packet despite the shaking I gave it. When I did the next yeast starter, I expected similar issues and gave the packet extra shaking, but the stuff just poured out with no noticeable clumping at all. Over the next day and a half, I noticed one had somewhat darkened and I even pulled them out from the back of the counter to make sure it wasn't just a difference in light. Had some family stuff come up and I had to put off my brew session the following day, so I watched the stuff darken further during the next two days. Sent a photo to White Labs and they said one likely just needed more time to settle out (had turned off the stirrer at that point). I let the stuff settle for a few more days and you can see how dark the starter on the left became. They both smell very similar, although my wife describes the one on the left as having a slight coffee ground aroma. I had expected them to smell radically different...but that was not the case. I can only assume some sort of contamination turned the one dark. Ended up disposing of it, splitting the other starter in halves and making two new starters and will proceed with my delayed brewing session on Thursday.

 

[Revvy]

Were these starters made with extract? What kind did you use, extra light, light or dark? It looks to me that you either used dark DME and the one on the left either never took off or took off really fast and flocculated out quickly OR you burnt the starter and the yeast either never took off or took off fast and flocculated quickly.

Yeast won't darken the wort, what we actually see is yeast in suspension actually makes the wort appear lighter and tan color, but once it settles out then you see the "normal" color of the "beer."

It is possible for two identical yeast to behave completely differently though, it's just the wildcard nature of living organisms.

Your stirplate on the left though, does it heat? I have a lab grade stirplate that can heat while spinning, it is conceivable that I could on mine actually do that if I had the heater on and cranked to full, I could probably accidentally carmalize my wort (and probably kill the yeast if not careful.) Can yours?

 

[XPLSV]

Both starters were used with the same brand of extra light DME, both boiled in the same pot, each for 15 minutes, etc. No heat on the stir plate. They were the same color at the start when placed on the stir plates...the one just continued to darken. I had also purchases both yeast packages at the same place on the same day. Haven't had anything like this happen before, I'm just guessing something got into the one package, either before I opened it or during my procedures. The dark one didn't smell awful or anything...I just decided not to take a chance.

While it didn't occur to me at the time, I could have easily boiled twice the volume of wort in one batch and split it into the two flasks, which would have made it even more interesting if given the same results.

 

[XPLSV]

I found an early photo of the starters before the one on the left began to darken. The difference from the start to the end is very stark.