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Oxygenate starter

Derek Toering

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Yes or no?

I can't see why not.  It is just a small version of brewing a beer.  You oxygenate wort for a normal ferment so why not a starter?

Some say yes...some say no.

I amusing a stir plate.  This keeps yeast suspended but I can't see that it introduces oxygen.

Derek
 
Oxygenate - yes.  It's to build up yeast and they need oxygen for this stage.  That said, you'll still get benefit even if you just bang your yeast into the starter wort.  Oxygenation will optimise conditions.

Using a stir plate will help this. If you have a vortex going, it will draw air in, mix it in for you, while also removing the CO2 (which helps the yeasties to grow).

That's why the calculators (BS2 included) adjust the volume or total cells produced depending on whether or not you use a stir plate
 
If you have an airlock on your starter flask or vessel, then I do believe that oxygenation is needed to help produce healthy yeast cells.  Under most other conditions, it really doesn't need much added oxygen -- especially when using a stir plate as dougie1st stated.

I make my starter wort and then allow it to come down to room temperature overnight while on the stir plate with the magnetic stirrer making a deep vortex to draw in oxygen as it mixes and cools.  The flask is loosely covered with sanitized aluminium foil to allow air to enter and exit the flask but it is folded down the sides to prevent contamination from falling in.  I don't oxygenate and get pretty decent cell growth from the starters.  The cells are viable and healthy when viewed under the microscope even after cold crashing.
 
Definitely oxygenate.  The conversation can lead to "how"? I have a stirplate and use it too.  Over at the AHA forum there's a bunch of talk of the "shaken not stirred" method where you basically shake the hell out of it just after pitching rather than using a stir plate.  I've tried this with success too... I do 10 gallon batches and split them, so if I do two different liquid yeasts I do one on the stir plate and one in a 1 gallon jug.
 
I am confused about adding oxygen.  In one hand the experts (Palmer) talk about adding oxygen to help the yeast.  On the other hand, they say don't use a secondary fermenter because oxygen can get in and spoil the beer.  ?????
 
vorpahdg said:
I am confused about adding oxygen.  In one hand the experts (Palmer) talk about adding oxygen to help the yeast.  On the other hand, they say don't use a secondary fermenter because oxygen can get in and spoil the beer.  ?????

The first stage the yeast go through when you pitch it into your wort is to take in nutrients and "fatten up" so to speak. Oxygen is essential at this stage. After fermentation is complete however oxygen is more of a contaminate that can spoil your beer and can adversely affect both the flavor and clarity of your beer.
 
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