Stir Plate - do you need the vortex

I thought the point of the Stir Plate was to Oxygenate the wort/yeast, not just keep it in suspension. Hence the need for a vortex.

How important is it to have the Vortex?

Using a 1 liter starter, I had a vortex, but after the yeast got going and there was some foam, the vortex was covered/shallow/ or else gone. I had to up the power to maximum to get it to come back.

I use a Stir Starter, and maybe I should consider adding more powerful magnets, even though the designer advised against that.



(My apologies - when I searched for this topic, before posting yet another repetitive already answered question, I used the wrong search string)

You are fine. You don't continually oxygenate your wort while fermenting beer, so the same applies with a starter. Once the initial growth phase is over the yeast are on to other things. At least that's the theory as I know it. My vortex is usually rather mild at the beginning and my starters work well.

I don't have an answer but I hope someone else does... I've been having the same issue. It can make a vortex in 2 liters of wort at the onset, but after a day it has trouble. Or what happens is, it will have a vortex and I will take the flask off the plate to mess with it, and after that a vortex is unattainable even though it was doing it before. I know Northern Brewer sells a 2" stirbar, I was thinking of getting one to see if it can solve my problem. The point of the stirplate is to keep optimum levels of oxygen in the solution with the vortex, so if its just spinning it around I don't think its fully doing its job

samc said:

You are fine. You don't continually oxygenate your wort while fermenting beer, so the same applies with a starter. Once the initial growth phase is over the yeast are on to other things. At least that's the theory as I know it. My vortex is usually rather mild at the beginning and my starters work well.

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The difference is, what is good for the flavor of beer and what is good for yeast are not totally connected. The yeast love oxygen, but it isn't best for beer. Any oxygenation that happens in the starter is taken care of in the beer so it isn't an issue. Yeast also love being in the 80 degree range, but that isn't an optimum temperature for the flavor of your beer. So I don't think you can totally compare the two IMHO

I'm not an expert, but from what I have read and listened to on podcasts it is about surface area. The more you have the greater the o2 transfer into the wort.

So is it required? I would say no. Does it help the cell count? All the data I have seen supports it.

You want to maximize gas exchange at the liquid-air interface to deliver the most oxygen possible. The best way to do this is to vortex. You could try a longer stir bar, but I'm not sure how well it would work with a StirStarter.

I use a lab-grade stir plate, a 5000mL flask, and a thick 4-inch stir bar. I can vortex the crap out of a foamless solution. Even with that level of overkill, the krausen will often stop the vortex until it falls.

I think a small dimple is fine. You dont really need a crazy tornado going on in there. I think people lose the vortex after a while because there are more solids(yeast) in the solution later on in the process.

I just pitched a starter on Saturday. I did not use a stir plate (don't have one...thinking of buying one). Followed the advice of a couple you-tubers and just put starter in a mason jar and swirled it every couple hours and boooooom. Within 6 hrs had solid evidence of fermentation in the primary and it went strong until this afternoon (about 48hrs). Hopefully it will turn out good. Going to do an experiment with this yeast as well. This batch was about 1060 amber ale and this weekend I am brewing a 1060-1070 IPA so I am going to try to just pitch that beer into the yeast of the other beer. I will post how it turns out...

Taco

a vortex is not needed. The movement of the stir bar helps to distribute the gas that dissolves at the surface. Without the kinetics added to it, it would require simple diffusion for the oxygen to disperse throughout the starter solution.

I think its all circumstantial. If you would like to simply wake up your yeast before pitching you might not even need stirring. If you would like some growth to get say 1.5x more yeast you might not need the vortex. Then if youre pitching to a big monster that needs 300 billion yeast cells then you might want a nice vortex to really get that yeast propagating. So Fast Stirring -> More oxygen diffusion -> more yeast growth. Id say let the last part in that chain dictate your stirring needs.

mlyday said:

I think a small dimple is fine. You dont really need a crazy tornado going on in there. I think people lose the vortex after a while because there are more solids(yeast) in the solution later on in the process.

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Everything I've read says this. As long as the yeast is swirling it's getting enough contact with oxygen to step up the cel count better. A stir plate is more effective than occasional swirling hence the smaller starter. A vortex looks cool but isn't needed, so there's no need to spend more money on bigger bars, magnets, or powerful motors to get the job done.

my gut feeling is that you want to facilitate gas exchange, the stirring keeps recycling the liquid to the surface where it can get rid of co2 and take on o2, by this logic a vortex isn't necessary. (whether or not my logic is correct...)
but if you have ever made a starter with intermittent agitation, when it's really going strong and you swirl it, look at the amount of co2 that comes out of solution. the stirring keps that coming out steadily all along, and doesn't require a vortex