Stirplate vs Airstone aeration on growth?

[jat147]

Hi,
My stir plate has become too much of a pita to be used much more. I'd like to switch to using constant aeration via a stainless airstone.
I figure that I'll still have the agitation that is enjoyed when a starter is stirred with a stir bar - but also benefit from increased oxygenation? Well, that's the hope?

The trouble is, yeastcalc doesn't have any data for aeration. Mr Malty does, but says that (quite a bit) more starter will be required with aeration.
Can anyone shed any light on this question please? Have you tried a comparison of your own? I just want to have an idea if a stainless airstone will be a step backwards.

 

[EarlyAmateurZymurgist]

You may want to reconsider your decision.

http://archive.maltosefalcons.com/tech/MB_Raines_Guide_to_Yeast_Culturing.php

 

[IL1kebeer]

Additionally, you will have a hell of a time controlling foam, even with foam control. I tried the same nonsense before I got a stirplate, and after losing tons of yeast to foamovers I wised up and got a stirplate. If you want to babysit your starter you could turn the aeration on and off every 30 minutes so you won't have foam issues but that would be more of a PITA than any stirplate issues. I personally was never satisfied with the results of the aeration stone method, but I guess you can try it for yourself if you really insist.

 

[flars]

Hi,
My stir plate has become too much of a pita to be used much more. I'd like to switch to using constant aeration via a stainless airstone.
I figure that I'll still have the agitation that is enjoyed when a starter is stirred with a stir bar - but also benefit from increased oxygenation? Well, that's the hope?

The trouble is, yeastcalc doesn't have any data for aeration. Mr Malty does, but says that (quite a bit) more starter will be required with aeration.
Can anyone shed any light on this question please? Have you tried a comparison of your own? I just want to have an idea if a stainless airstone will be a step backwards.

What is the problem with your stir plate? Perhaps we can help.

 

[jat147]

What is the problem with your stir plate? Perhaps we can help.

Yeah, good point.
The plate works ok with small volumes. For a 1-2L starter it is no trouble, but I'm stepping them up in 3 stages to make a really big starter. When I get to volumes of about 10L the bar just wont spin due to the density of the yeast in the starter. Either that or if I spin the fan faster the magnet cant stay held and just flies off.

I think what I should use is a shaker table, but the prices are too much.
I haven't considered foaming, but that is a big problem.

 

[flars]

Yeah, good point.
The plate works ok with small volumes. For a 1-2L starter it is no trouble, but I'm stepping them up in 3 stages to make a really big starter. When I get to volumes of about 10L the bar just wont spin due to the density of the yeast in the starter. Either that or if I spin the fan faster the magnet cant stay held and just flies off.

I think what I should use is a shaker table, but the prices are too much.
I haven't considered foaming, but that is a big problem.

I have just had the same problem. I normally use a one inch crosshatch style stir bar. Thick yeast did stop it a couple of days ago. I dropped in a 2 inch stir bar. The 2 inch worked. I had discontinued using the 2 inch because in a starter of less than 1.5 quarts it created a vortex much greater than necessary.

 

[jat147]

I have just had the same problem. I normally use a one inch crosshatch style stir bar. Thick yeast did stop it a couple of days ago. I dropped in a 2 inch stir bar. The 2 inch worked. I had discontinued using the 2 inch because in a starter of less than 1.5 quarts it created a vortex much greater than necessary.

I've been messing around with the plate today, and the collection of stir bars I've got. I find the 2 inch bar gets thrown off the plate at most speeds, but the 1 inch seems to find it easier to stay on the magnet - even when the rpm is increased. However, these are currently tests with water, so the effect may be very different in a thick slurry?
I use the 2 inch as a first choice as it'll make a bigger vortex, which seems to make more sense. I guess a bigger magnet would grip the bigger bar at high speed, but when I increase the magnet size it has a negative effect on the fan, which burns out quickly.

What is a crosshatch stirbar?

 

[flars]

I've been messing around with the plate today, and the collection of stir bars I've got. I find the 2 inch bar gets thrown off the plate at most speeds, but the 1 inch seems to find it easier to stay on the magnet - even when the rpm is increased. However, these are currently tests with water, so the effect may be very different in a thick slurry?
I use the 2 inch as a first choice as it'll make a bigger vortex, which seems to make more sense. I guess a bigger magnet would grip the bigger bar at high speed, but when I increase the magnet size it has a negative effect on the fan, which burns out quickly.

What is a crosshatch stirbar?

The crosshatch stir bar is like two 1 inch stir bars perpendicular to the other. More like a + design. I had been using a flask with a domed bottom. This stir bar had more stability for that flask.

I also found a company that makes ceramic stir bars. The bars can be made to custom lengths. The longer lengths can be just shy of the diameter of the container being used. These would be impossible to be thrown. Price around $100. To high for me.

 

[BigFloyd]

Yeah, good point.
The plate works ok with small volumes. For a 1-2L starter it is no trouble, but I'm stepping them up in 3 stages to make a really big starter. When I get to volumes of about 10L the bar just wont spin due to the density of the yeast in the starter. Either that or if I spin the fan faster the magnet cant stay held and just flies off.

If you're making 10L starters, you maybe ought to think about instead doing a 5-gallon 1.040-1.050 starter beer with the same strain and using the slurry from that first fermentation.

 

[EarlyAmateurZymurgist]

if you're making 10l starters, you maybe ought to think about instead doing a 5-gallon 1.040-1.050 starter beer with the same strain and using the slurry from that first fermentation.

+1