Yeast starter working?

[camonick]

Tried the search function but couldn’t find an answer. I am doing my first starter right now. How do you know if it’s doing anything/ growing? I made a 1 liter starter in a 2 liter flask and it’s on a stir plate with a decent whirlpool in the center. The opening is plugged with a foam stopper. I plan to pitch it (WLP004) late tonight into an Irish Stout ≈1.044 OG. It should be 24+ hours since it was started. The pure pitch packet was not quite 3 months old and the brewer’s friend calculator says a 1 liter starter should still be large enough.
Thanks
Nick

 

[VikeMan]

With a stir plate, you might not see much krausen, but the color will change and become more opaque and cloudy.

 

[camonick]

With a stir plate, you might not see much krausen, but the color will change and become more opaque and cloudy.

Thank you. The color has changed considerably and I can see a bunch of CO2 rising if I look closely at the edges. I’m about 2 hours from pitching it into my wort.