Wyeast 3787 starter oddness

[johnnysoj]

I had a question for you guys.

Something happened today that I haven't seen before. On Saturday I made a 1.035 starter of Wyeast 3787 for a brew day today. I've made many starters in the past, with this yeast, and others as well. While it was on the stir plate, I didn't see much activity. Usually it gets a bit frothy, but this time practically nothing. I did notice that the smack pack never really inflated, and the mfgr date was 01/14, which is still good I suppose. I stopped the stir plate last night and put the yeast in the fridge to settle out. the starter was pretty dark, and it never completely settled out, but there was about a 1/2 inch of yeast on the bottom of the flask. I wasn't sure if it fermented. So, today, right before I pitched into my wort, I decanted some of the spent starter into a hydrometer to check and see if the gravity changed. My thought was if it was sluggish or dead, I'd just pitch a backup of US05. The odd thing was that the whole starter was carbonated! It looked like I poured a regular beer into the hydrometer... I figured Ok, I guess the yeast is working, so I didnt get a reading, and just decanted all but just enough to get the yeast into suspension and then pitched. It seems to be doing its thing, but why was it carbonated? I've done a bunch of starters in the past, with at least 5 or ten different strains and none of them were carbonated.

thanks
J.

 

[dinnerstick]

sounds like it was pretty active when you stopped stirring, enough to supersaturate with CO2, which stayed in solution in the fridge where liquids can hold a lot more gas in solution, and came out of solution when you poured into the cylinder at room temp. that's my educated guess anyways. if you had kept it on the stir plate the stirring would have knocked that gas out of solution as it was being generated. the good thing is that it's a great sign that your yeast were nice and active, even if they were a bit sluggish out the gate.