I need some reassurance on infection risk of starters. help!!!

[HOPSareKEY]

Hello all,
I have been brewing for quite some time, but have never done a starter yet. I am about to do one and I am paranoid about infection.
When we direct pitch yeast into a beer, we immidiatly put on the airlock to keep out oxygen and foreign material. With a starter, we keep a loose cap on to allow oxygen.
Why is a loose lid ok for starter, but not beer?
Thank you

 

[hlm123]

The loose cap is perfectly fine for the beer as well, at least until active fermentation is finished. The basic idea is that no contaminants are going to crawl up into the fermentation space, and the amount of oxygen that is going to be let in is minimal especially with carbon dioxide rushing out. When your yeast starter is working, on the other hand, you WANT oxygen to get in, which is why you use a stir plate, since you're trying to grow yeast cells.

This might make you think twice about the dangers of air exposure...

 

[kaconga]

Starters can get infected. Mine got infected just today. I had a fruit fly crawl under the foil and get into my starter. If you are really paranoid about it then I recommend getting a foam stopper. It would keep most everything at bay while letting O2 pass through.

 

[flars]

A coffee filter and a rubber band will work also. Just read a post someone was using this method for covering the starter flask. Also kept the filter moist with a spray of Starsan solution.
I use sanitized foil on the Rubbermaid container I use for my stir plate starters.

 

[HOPSareKEY]

pretty impressive, but We don't know if they have a crazy ventilation system or whatnot though. And I understand Belgians have been brewing beer for ages in open vats, but they're in a proper region for it and the style suits it.

I can see when active co2 is being produced there not being much of a problem, but what about the few hours before and after when the vigorous fermentation stops. In beer, it's safe cause it's the airlock method, but starters are exposed during that time.

 

[Wolfbrau]

Why is a loose lid ok for starter, but not beer?

I believe a loose lid is fine for the whole batch, too, as long as you keg or bottle it after it's done conditioning (and no later). Airlocks are really a matter of convenience, not necessity. They help a homebrewer monitor relative fermentation activity and help prevent infection after fermentation is finished, during conditioning and transfers.

In general, it takes a homebrewer longer to achieve the same level of conditioning as a commercial brewer, so commercial open fermentors have relatively little loiter time; thus, commercial brewers have lower exposure to pathogens. Not to say you can't totally open ferment as a homebrewer in the right circumstances.

Short version: Airlocks are there so you can count bubbles and keep it in primary longer than most commercial brewers, neither of which matter in a starter.

 

[tally350z]

In theory you are making a small beer, so the only issue when it comes to oxygen is extended periods of aging. Which will never occur from a starter because of the quick turn-around 36ish hours.
What will be your method in making the starter? Stir plate, shaking? If using a stir plate you will notice the CO2 coming out of suspension with a little ring of bubbles on the top portion of the starter. Once that subsides the yeast have done there thing. For my starters I boil on top of an electric stove, so I add the water,DME, stir bar and cover with foil, bring it to a boil and than chill.

 

[HOPSareKEY]

ok thank you for the feedback. I also have one other issue. im not fully impressed with the yeast calculator im using in the fact that they have 2 very big differences if you use jamils way or the other guys.

I will be using a stir plate and my og will be in the 1.080-90 vicinity on an oatmeal stout. how much dme, how much water, and how many packs of wyeast irish ale should I use?

 

[tally350z]

Check out yeastcalculator.com that is the one I use and it works good for me. It says for a 5.5 gallon 1.085, you will need roughly 320B cells. With one pack you could do a 1.6 Liter starter and it will be ok. The ratio I use is for 100ML of water use 10grams of DME, so 1.6L you will need 160 Grams DME.