Fermcap S: Height of activity in yeast starter?

[wbtenor]

I have a stuck fermentation that I'm going to try to fix by pitching a healthy starter of WLP099 (High Grav) at high krausen. Trouble is, I pressure canned my wort with foam control (fermcap S: 1 drop for 2 gal), so no krausen. This is my first experiment with foam control. For a regular starter, I let it ferment out, decant, and pitch. Since I don't have any krausen here, when is the peak of fermentation to pitch into my stuck batch?

 

[duboman]

It's very difficult to tell when using foam control, sometimes you can discern a debris ring just above the level of wort on the glass but only maybe 1/8" or so above.

 

[jtejedor]

You can usually go by the visual indicators that a starter is done. The color lightens up, you get that milkiness. And even with foam control if a considerable amount of fermentation has gone on I still get head when I swirl the starter around myself. If you are really concerned you could take a gravity reading on the starter to make sure it fermented out.

 

[Calder]

The wort will be cloudy. You are looking for actively working yeast.

 

[wbtenor]

Thanks all. The starter is definitely done (not at peak). I think I'll decant and pitch more wort in now that I know the warning signs. I have a long way to go on this stuck ferment, so more yeast isn't going to hurt