How likely is it for a starter to become infected?

[flyfisherwes]

I don't want this to be that panic infection thread. I'm just wondering if its really that likely for a four cup starter to become infected when you pitch enough liquid yeast for 5 gallons of beer. I mean I'm sure its unlikely if you follow great sanitation practices, but what if you were to leave a starter exposed to open air or drop a small unsanitized object in? Could you tell if it was infected?

 

[passedpawn]

I don't want this to be that panic infection thread. I'm just wondering if its really that likely for a four cup starter to become infected when you pitch enough liquid yeast for 5 gallons of beer. I mean I'm sure its unlikely if you follow great sanitation practices, but what if you were to leave a starter exposed to open air or drop a small unsanitized object in? Could you tell if it was infected?

I tried to grow yeast from a bottle of some belgian beer. I have pretty good sanitation (boil starter wort in flask with stir bar, etc), but a week after I added the dregs I had some mold colonies growing on the surface. So, it's possible.

 

[flyfisherwes]

I tried to grow yeast from a bottle of some belgian beer. I have pretty good sanitation (boil starter wort in flask with stir bar, etc), but a week after I added the dregs I had some mold colonies growing on the surface. So, it's possible.

But thats a different situation. You only had a few yeast from a dreg. I'm talking when you pitch a hundred thousand yeast into just a little starter. wont the yeast eat most infections up too?

 

[aiptasia]

You should be able to tell easily enough. Moulds, bacteria and other nasties will look and smell a little different than fermenting yeast. The goal of sanitizing isn't complete sterilization of your equipment and methods, just giving the yeast the upper hand to establish themselves before the other bugs infect the wort.

If the starter doesn't look or smell right, it's probably having a problem of some sort. Trust your gut. At the worst, get some fresh yeast from your brew shop and just pitch without using a starter. Most of the wyeast and white labs vials and fermentis packets will work at one container per 5 gallon batch by direct pitch with no starter. Add two for a 10 gallon, etc.

 

[BBL_Brewer]

But thats a different situation. You only had a few yeast from a dreg. I'm talking when you pitch a hundred thousand yeast into just a little starter. wont the yeast eat most infections up too?

The yeast won't eat other microorganisms, but they will colonize the wort faster and inhibit other growth just by sheer number of cells present. Once the wort gets fermented it is less susceptible to infection, but still possible.

 

[Mcsuck]

The yeast won't eat other microorganisms, but they will colonize the wort faster and inhibit other growth just by sheer number of cells present. Once the wort gets fermented it is less susceptible to infection, but still possible.

Colonize faster probably isn't the most accurate since most bacteria replicate about 3x faster than yeast however I do agree with you that it is the sheer number of yeast cells that give them the advantage.

 

[Hang Glider]

... but what if you were to leave a starter exposed to open air or drop a small unsanitized object in?

personally, I wouldn't take that chance. If I knew I did something unsanitary, I wouldn't cross my fingers and pitch it - I might ruin all my work. That's when you pull out your emergency pack of Notty and move on.

 

[QueenCityALER]

If you practice good sanitation and preferably in a container that can be air-locked, you shouldn't have any problems with wild yeast, bacteria, and other nasties. I also agree with the other folks that you should trust your 5 senses. If it looks bad, smells terrible, and tastes bad (if you dare to taste your possibly infected starter) then it probably is bad. Why risk ruining 5 gallons (or whatever size batch you're making) with an infected starter. It makes better sense to just buy more yeast and pitch it direct. I do this with many of my beers. A beer with a gravity of 1.050 or higher, I pitch 2 packages of dry, or liquid yeast. For me, I love to use slurry from a previous batch. Not only does it have ample healthy yeast, but it's already paid for. If I'm making a batch that would need the same yeast as the previous batch, I'll very carefully run my chilled wort right into the same primary as a previous batch, onto the yeast cake, and aerate thoroughly, given the new beer calls for that yeast and on brew day it is time to rack the original beer. I've practiced this many times and always with great results. And, it'll save you a few bucks. Back to the thread: A starter is a wonderful idea and in many brewers opinions a must for every batch. However, every extra process you engage in making your beer the more chances that your beer can pick up bad stuff. If you are really uncertain, I'd buy 2 packs of yeast, and skip the starter all together. Besides, each pack of yeast you buy contains the baseline minimum of yeast to get a 5 gallon batch to ferment, so don't worry about over pitching. As a matter of fact, if you use only one pack of yeast no matter what style you are under pitching anyway. This is the equation Commercial breweries and myself use: 1 million yeast cells per degree Plato per milliliter of wort. If you don't use Plato, then for purpose of ease, assume degrees Plato are equal to specific gravity divided by four. Do the math. You'll be surprised at the results. Under pitching is a widespread issue, that many home brewers don't even know about or acknowledge. Seriously. Do the math.

 

[flyfisherwes]

My starter smells and looks healthy. It started off smelling like bread baking. It had a big frothy krausen and it doesn't look like there is anything growing on it. I just wondered because I dropped the lid to the liquid yeast into the starter while pitching. I'm also using a glass pitcher to make the starter in. I usually use a big wine bottle but it wasn't available. I covered it with foil and all but I was just wondering because it sparked a lot of questions with me.

 

[flyfisherwes]

I haven't tasted it yet but I will after I cold crash it.

 

[BamaRooster]

If you practice good sanitation and preferably in a container that can be air-locked

Using an air-lock while making a starter is not recommended, the yeast need to take up oxygen for the largest benefit. I common practice is to place a tin foil sanitized cap over the starter container. +1 on the sanitation!!

 

[flyfisherwes]

Looks fine. Smells a bit fruity.

 

[flyfisherwes]

So if I taste it and it tastes alright I'm good?

 

[Sardoman]

Yes. If your spent starter beer tastes OK then you are in good shape. It's good practice to taste it every time, just to be sure before you pitch. You expect it to be fruity because it fermented at room temp.

If the starter tastes wrong then just break out that pack of dry yeast you have in the refrigerator.

 

[flyfisherwes]

Great thanks. I actually have another pack of the liquid yeast.

 

[flyfisherwes]

How will I know when it's done fermenting? It still has about 3/4 inch of Krausen

 

[flyfisherwes]

Well I had split the starter up into two parts. One of the parts would have ben really good had it been hopped. So I think the starter is ok. I will taste the other half tomorrow before I pitch. See if it's good. It was my intended pitching part anyway. The one I tasted will serve as a starter to Starters to some more brews. I'm a cheap ass. I like this liquid yeast. And I refuse to get less than 7 brews out of a 7 dollar vial.