Stir Plate Proofing

[Brewham]

Am using a stir plate for the first time and notice that after 24 hours there is no activity - no kreusan, no bubbling. I did starters before in a container and about this time, I would always have some evidence of activity. If I shook the container, there would be outgassing.

Is no obvious activity normal because the stirrer keeps the yeast in suspension and there is no opportunity for gas to build up because it is being stirred out?

If so, how do you tell if your yeast is alive and well?

 

[marubozo]

With a stir plate the yeast are constantly in suspension so over time you should notice the liquid become more pale, or milky in color. In my experience there's virtually no karusen visible like you'd get in a still container. So what you are describing sounds normal.

If you want to see what's going on, just turn the stir plate off and let it sit for a while and you'll see a ton of yeast settle on the bottom which will show there's a lot going on in there even if it isn't immediately visible.

 

[Brewham]

Thanks, I'll give the no-whirl test a whirl.

 

[Montanaandy]

I usually get either a small amount of krausen or quite a bit (depending on the yeast) after 24 hrs on the stir plate.

*What type of yeast are you using?

*What was your starter comprised of (i.e. how many cups of DME to water ratio)

 

[marubozo]

Here's one of my more recent starters, and this is about the most activity I've ever seen while on my stir plate. Obviously there are some bubbles, but because of the constant motion it never grows beyond just a thin layer.

 

[Montanaandy]

Yeah the pic represent what you want to strive for - small amount of krausen and a lot of bubbles in the flask. However some yeast is more active on the stir plate than others (PacMan and Irish Ale come to mind).

That has to be the nicest looking stir plate that I have ever seen. Montanaandy

 

[Wolfy]

I think the stir-plate behavior really depends on the yeast.
This is the most recent starter I made, and the yeast (active top cropping English Ale yeast) is crawling out of the top of the flask:

The plastic tub is not as pretty as marubozo's stir plate, but it's needed with the yeast I was using.