Aquarium pump instead of stir plate

Hi all, would it be possible to use a small aquarium pump in place of a stir plate to aerate a starter?

If so, would it be necessary to have the pump on a timer or could it be left on indefinitely?

Thanks!

Cool idea.

Would you have a pump blow air bubbles into the yeast, or circulate the yeast through the pump to splash it around a bit?

With the latter you might run into problems as the yeast thickens up towards the end of the process, I'm not sure.

I'd just drop the stone into the starter, I'm looking at building a stir plate but need to order a couple of things then this popped into my head. It serves the same purpose so I'm thinking it must work. I've heard over aerating is bad though so I assume I'll need to put the pump on a timer

The purpose of a stir plate isn't just to introduce oxygen it is to keep the yeast in suspension and to knock the CO2 out of the liquid so just an air pump and stone won't have the same affect. You would be better off just periodically giving it a shake/swirl to get the yeast back into suspension and introduce some oxygen.

This is interesting. I say go for it. I would be concerned with the potential of the starter being sucked into the airline while the pump is off. Though if you don't have it off for long (less than an hour) it shouldn't be a problem.

WrQth said:

The purpose of a stir plate isn't just to introduce oxygen it is to keep the yeast in suspension and to knock the CO2 out of the liquid so just an air pump and stone won't have the same affect. You would be better off just periodically giving it a shake/swirl to get the yeast back into suspension and introduce some oxygen.

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An air pump on a timer should be just as effective at keeping yeast in suspension as periodic shaking/swirling.

It would also be very effective at knocking CO2 out of solution. I keep planted aquariums, and hobbyists often inject CO2 into the aquariums as a source of carbon for plants. It's well known in the hobby that if you're using an air pump in conjunction with CO2 injection, you'll have to increase your rate of CO2 injection to compensate for the off-gassing caused by the air pump.

An air pump connected to a timer set to come on for 60 seconds every 15 minutes would be a great place to start.

C'mon, do it!

So I still haven't actually made the starteer, may be doing it tonight. Was looking at mrmalty's FAQs and the below is pretty interesting

Continuous air from a pump and sterile filter can be effective too. The major drawbacks are being able to control the flow of air to prevent excessive foaming and evaporation of the starter. Shaking is just as effective as intermittent aeration with a pump.

So hopefully putting the pump on a timer, say 15 minutes every 3 hours (completely uninformed guess) will get me 'shake' results without the need to keep an eye on it