Yeast Starter: Stir Plate vs O2?

The biggest advantage of the stir plate is to keep the yeast in suspension, keeping them in suspension promotes growth and speeds that process up. Otherwise they will just clump and floculate.

As far as I know the only reason not to oxygenate the stirred started is that the agitation to keep yeast in suspension will bring the O2 out of solution.

 

Stir plates transfer the CO2 out of solution depressurizing the starter, they also bring in O2 from the ambient air (unless you have a way to seal off the opening completely). You could add pure O2 to the starter every so often but that is a lot of extra work as you would need to sanitize the stone and wand each time, clean it after every use, and run the risk of letting other stuff into the starter every time you open the top. This could be combatted by leaving the stone and hose in the starter the whole time with the foil over it all, then hitting it with O2 as needed, but that runs the risk of acting as a siphon if the hosing drops too low. And you have to remember to do it. Ramble, ramble, ramble, Stir Plate.

 

No, not redundant. different tasks.
the primary purpose of the Oxygen stone is to get oxygen into the cooled wort. the boiling of the wort results in very little oxygen being present after cooling. adding oxygen with a stone is the best way to get the wort saturated and quickly.

a starter with a stir plate is the best way to increase the cell count of your yeast colony.

two different tasks requiring different techniques.
Cheers.

 

+1

 

Yeast need oxygen to promote production of sterols, the best growth rate possible, and be in peak health when tasked with fermenting beer. A healthy fermentation generally produces 3-6X the amount of cells that it started with. The stir plate gets you off to a better start cell count wise, which will then be multiplied 3-6X over during the batch fermentation. The stir plate gets oxygen to your starter, removes co2, keeps the yeast in suspension, speeds up the starter process, and makes it a "set it and forget it" affair. It is 100% worth the money. It will pay for itself in enough time, considering how much less yeast you will need to purchase, let alone improve the quality of your beer!

 

And DME.

 

I'm going to go against the consensus here and say I think using the wand could be equally effective.

The purpose of the stir plate is to aerate the starter wort and promote cell growth. Any benefit from keeping the yeast in suspension is marginal for our purposes here. We are not particularly concerned about full attenuation (which is going to occur almost no matter what you do when you drop ~100B cells into ~1L of wort), so having the yeast floc prematurely is not a significant issue, given normal temperatures etc. We are hoping to produce a raised level of oxygen during the yeast's adaptation phase, which will promote reproduction. I think you could do this very effectively with an oxygenation stone.

Now, I don't do this, because I have a stir plate, and I don't want to waste oxygen, which isn't cheap. But I think it'd work fine, particularly if combined with intermittent shaking.

 

I just shake mine whenever I walk by it.

 

No doubt stir plates be cool HB swag but drive-by shake and swirls work just as well.

 

This is true, as long as you don't mind making a bigger starter to get the same amount of cells.