Foaming Yeast Starter

[Aaron Rennie]

Here is my next issue. My yeast starters seem to foam excessively.

Both this and the last one foamed right at the start of fermentation, is this normal?
Should I start the sir plate after initial fermemtation?
Should I speed the stir plate up, currently as slow as possible to stop if foaming over.

 

[RoomWithABrew]

Bigger flask would do it, or smaller starter!


What yeast are you using ? usual 1040 wort?
I have mine running with a little vortex in the surface.
More usual that my starters are like this second one,

 

[Aaron Rennie]

Bigger flask would do it, or smaller starter!
View attachment 49596

What yeast are you using ? usual 1040 wort?
I have mine running with a little vortex in the surface.
More usual that my starters are like this second one,
View attachment 49597

Thanks @RoomWithABrew, this was helpful. As feared I'll need to invest in a bigger flask.

I've started making 2l straters so I can decant 500ml off to store. This one is an Irish Ale Yeast (WLP004).

 

[foxbat]

Flasks are like kegs. One is never enough. I think I've got all bases covered now:

 

[Aaron Rennie]

The correct equation for anything homebrew is always:

Y+1 = Correct amount

Where y is the item in question,

@foxbat where do you get them from

 

[foxbat]

The correct equation for anything homebrew is always:

Y+1 = Correct amount

Where y is the item in question,

@foxbat where do you get them from

Cream Supplies, but it was a while ago and stock items seem to come and go at that place. For example they don't have the 5000ml at the moment. Best price for one of those biggies at the moment is at Cole-Parmer. I think I paid about £25 at Cream Supplies when I got mine so not much difference today. Anything above 2 litres - in other words any lager starter - goes into the 5000ml flask.

 

[Aaron Rennie]

Thanks, looks like I'll be purchasing another flask.

It's a stupid question but should I get a 3L or.....just go straight...... to the 5L?

..... 5L it is

 

[Aaron Rennie]

.

 

[Northern_Brewer]

Should I speed the stir plate up, currently as slow as possible to stop if foaming over.

People generally overspin their starters, all you're aiming to do is keep the yeast in suspension. So keep it slow.

If you're having problems with foaming, add some anti-foam. Simet(h)icone is the stuff you want, you can either buy versions that are "officially" for brewing - FermCap and the like - or it's available from pharmacies formulated to stop "foaming" in your belly, it's the basis for most anti-wind medication. The medical versions work fine, you just have to watch that in tablet form there may be a bit of extra chalk etc entering your water (less of an issue for starters) It may not be a lot cheaper that way but it can be handy to pick some up from supermarket/pharmacy if you've not got a brewing order planned in the near future.

 

[DocAnna]

People generally overspin their starters, all you're aiming to do is keep the yeast in suspension. So keep it slow.

May I argue for the latter, that more rapid spinning is more desirable and will minimise the foaming. Foams are less stable in moving fluids and will reduce with more rapid spinning. The aim is not just to maintain the yeast in suspension but to increase oxygen availability which a more rapid movement and vortex will better achieve. Short of spinning the yeast so quickly it caused mechanical lysis of the cells, which would seem very difficult to achieve at homebrew scale, it's hard to see how something could be 'over' spun in a starter?

Anna

 

[Northern_Brewer]

May I argue for the latter, that more rapid spinning is more desirable and will minimise the foaming. Foams are less stable in moving fluids and will reduce with more rapid spinning. The aim is not just to maintain the yeast in suspension but to increase oxygen availability which a more rapid movement and vortex will better achieve. Short of spinning the yeast so quickly it caused mechanical lysis of the cells, which would seem very difficult to achieve at homebrew scale, it's hard to see how something could be 'over' spun in a starter?

Anna

The incremental oxygen from fast spinning is not enough to benefit the yeast, whereas the mechanical shearing from fast spinning stresses it. Overall slower is better.

 

[DocAnna]

The incremental oxygen from fast spinning is not enough to benefit the yeast, whereas the mechanical shearing from fast spinning stresses it. Overall slower is better.

http://braukaiser.com/blog/blog/2013/03/25/stir-speed-and-yeast-growth/Does suggest otherwise. From a pragmatic perspective, yeast are single celled wee beasties that can't get stressed as such by movement unless there was something that actually broke the cell open, they can't shear as such other than altering cell shape which on the single cellular scale involved would involve massive acceleration forces. While I may be quoting the braukaiser article, I do wish people doing experiments would run them more than once with controlled conditions, at present the article represents a case study which isn't really conclusive, and why can't we see some statistical p values for the sample comparisons? Sometimes I think it would be good to take a few months off, hire some lab time and properly answer some of these questions in a robust scientific manner.

Anna

 

[johncrobinson]

I do agree doc yeast are very robust little critters

 

[RoomWithABrew]

@Aaron Rennie
Not sure why you want to save 500ml of yeast, a thin settled layer in a 50ml sterile pot will give you plenty to build up for a next batch. If necessary for your bank then several 50ml pots. That would give you a bit more head space in that smaller flask.
The smaller flask also useful for building up the yeast before making the big volume.
But 2000ml flask is sort of no mans land really.

 

[marshbrewer]

The correct equation for anything homebrew is always:

Y+1 = Correct amount

Where y is the item in question,

@foxbat where do you get them from

The correct answer is as follows;

Q: How many pieces of homebrew equipment do I need?

A:. (X+1)=(Y-1)

Where;

X = the number of pieces of homebrew equipment you have now
Y = the number of pieces of homebrew equipment it would take for your significant other to leave you.