Signs of Fermentation in Starter

[taa800]

I'm in the middle of making my first yeast starter. I mixed 750 ml of water with 75 g DME. I'm only brewing a 3 gallon batch. I put it in a 2 liter bottle and pitched the yeast. After a day, I don't see what I thought I'd see in the bottle. I was expecting active fermentation where I'd clearly see the liquid bubbling. Does that not happen with a starter of this size?

Thanks

 

[BigFloyd]

I'm in the middle of making my first yeast starter. I mixed 750 ml of water with 75 g DME. I'm only brewing a 3 gallon batch. I put it in a 2 liter bottle and pitched the yeast. After a day, I don't see what I thought I'd see in the bottle. I was expecting active fermentation where I'd clearly see the liquid bubbling. Does that not happen with a starter of this size?

Thanks

Sometimes a starter will show plenty of visible signs of fermentation, sometimes not (especially on a stir plate).

If you want to check to see if it's producing CO2, put some sanitized (sprayed w/ starsan) plastic cling wrap over the top and secure it with a rubber band. If the wrap starts to bulge up, it's active.

 

[flars]

I'm in the middle of making my first yeast starter. I mixed 750 ml of water with 75 g DME. I'm only brewing a 3 gallon batch. I put it in a 2 liter bottle and pitched the yeast. After a day, I don't see what I thought I'd see in the bottle. I was expecting active fermentation where I'd clearly see the liquid bubbling. Does that not happen with a starter of this size?

Thanks

Are you using a stir plate or intermittent shaking method?
On a stir plate there is very little evidence of a krausen. Active fermentation will change the wort to a milky white color.
Active fermentation with the intermittent shaking method will form an instant krausen when the container is shaken and swirled.

 

[taa800]

I am not using a stir plate. I'm just shaking the bottle from time to time. When I do shake it, I put the cap on tight and shake it. That pressurizes the bottle, where I have to loosen the cap to relieve the pressure. After I let the bottle sit, I don't see any bubbling at the top, but there is a small layer of foam. Maybe a quarter of an inch.

I guess I was expecting to see a lot of bubbling. I use plastic fermenters so I've never really "seen" a fermentation. So maybe I need to change my expectations on what it should look like.

 

[flars]

I am not using a stir plate. I'm just shaking the bottle from time to time. When I do shake it, I put the cap on tight and shake it. That pressurizes the bottle, where I have to loosen the cap to relieve the pressure. After I let the bottle sit, I don't see any bubbling at the top, but there is a small layer of foam. Maybe a quarter of an inch.

I guess I was expecting to see a lot of bubbling. I use plastic fermenters so I've never really "seen" a fermentation. So maybe I need to change my expectations on what it should look like.

An active fermentation should produce a heavier krausen layer than what you are experiencing. The starter wort needs periodic oxygenation for the yeast to do their best. Try shaking the bottle without the cap on. Carefully of course. This will allow the CO2 that was produced to be displaced by oxygen. After a few hours you may see a thicker krausen layer forming.

 

[Rockindaddy]

When I make my starters, I don't see much activity. Maybe a little foam on top like yours and they always work fine. I don't use a stir plate either, just shake every once in awhile. If your bottle is pressurized when you undo the cap I think your getting activity.

 

[EarlyAmateurZymurgist]

Unless the culture is very fresh, it usually takes two days for many yeast strains to reach that level of fermentation in a starter.

I see that you are using a 10% w/v solution, which is good. However, you may want to try a 7.5% w/v solution next time. That's what I use when making growth media. Additionally, I pretty much specialize in 3.5 gallon primary vessel batches. I usually only pitch a stirred 500ml starter when fermenting ales. Heck, even a stirred 300ml starter works well at this volume.