starter question... airlock?

[LSDracula]

Well in my next brew I planned on using a properly prepared starter. Last time I made a starter which I stepped with 3 different wort additions I found out this is only necessary for lagering. That starter was extremely oxidized and even smelled bad so I decanted. This round I plan to make a 2qt starter in a gallon jug the day before brew day and pitch the whole thing on brew day. Hopefully during high krauzen.

Using this method wouldn't it be better to use an airlock to avoid any oxidization in the starter product? Since it is going strait into the beer.

 

[enderwig]

Airlocks are never recommended for starters, a starter needs all the oxygen it can get, just cover it loosely with foil.

 

[Synovia]

Airlocks are never recommended for starters, a starter needs all the oxygen it can get, just cover it loosely with foil.

I don't understand how thats going to give it more oxygen. As soon as it starts fermenting, you'ce going to get teh CO2 blanket over the wort.

 

[Snafu]

+1 on the foil. Not sure why, but several books I have say its to allow it to 'breathe". Incidently, I use this simple formula for my starters and I usually always get a 040 starter. 1000ml water and 100g's of DME. easy peasy

 

[enderwig]

I don't understand how thats going to give it more oxygen. As soon as it starts fermenting, you'ce going to get teh CO2 blanket over the wort.

If you don't use a stir plate, you should shake it as often as possible.

 

[Synovia]

If you don't use a stir plate, you should shake it as often as possible.

Even with a stirplate, you're still not going to suck O2/Air back into the flask I don't think.

 

[enderwig]

Even with a stirplate, you're still not going to suck O2/Air back into the flask I don't think.

From MrMalty Fourteen Essential Questions about Yeast Starters

There are several ways to add oxygen: intermittent shaking, a stir plate, pure oxygen, or an air pump with a sterile filter.

A stir plate is perhaps the most effective method. When using a stir plate, don’t plug up the starter vessel with an airlock. A sanitary piece of aluminum foil or a breathable foam stopper is all you need. Bacteria and wild yeast can’t crawl and a loose fitting cover will allow for better gas exchange.

Shaking the starter as much as possible, every hour or two, makes a large difference in the amount of yeast growth and health. With enough attention and good air exchange, shaking is just about as effective as a stir plate.

 

[The Pol]

Yeah, this is yeast starters 101...

Do not place airlocks on your starters. It traps the O2 and doesnt allow any exchange of gasses.

This has been scientifically proven, airlocks on starters only hinder yeast growth.

Foil is your friend, and it is easier/cheaper

 

[Synovia]

Wonderful, but that doesn't exactly explain how a stir plate pulls O2 down through the CO2 layer.

Shaking? Of course, you're basically purging the thing of air.

 

[Yooper]

Wonderful, but that doesn't exactly explain how a stir plate pulls O2 down through the CO2 layer.

Shaking? Of course, you're basically purging the thing of air.

A stir plate keeps the yeast in constant suspension, which is the main reason it works so well. I think there is some o2 pulled into the vortex, though, but not all that much.

 

[enderwig]

Wonderful, but that doesn't exactly explain how a stir plate pulls O2 down through the CO2 layer.

Shaking? Of course, you're basically purging the thing of air.

It takes very little agitation to displace your CO2 layer, thats also why it recommended to not open your fermenters, the little agitation and air flow over the opening displaces the blanket of CO2.

 

[ajf]

Check out http://maltosefalcons.com/tech/yeast-propagation-and-maintenance-principles-and-practices
The first bar graph shows the effectiveness of a stir plate, and I think her qualifications far outweigh mine.

-a,