Why do yeast starters help?

Yeast gets into the wort. It each sugars and reproduces. When the yeast runs out of oxygen and sugar, then it flocculates and goes to sleep at the bottom of my carboy.

When I make a starter, I begin a miniature version of the process. After the initial yeast have reproduced a couple times, I throw the starter into the big carboy to continue the process in there.

So (other than speeding up the fermentation process, which I get) what benefits does a starter provide? Yeast still have the same sugars and oxygen to eat in the carboy and they will keep eating and reproducing until those things are gone. Whether they start eating in a start or in the carboy shouldn't make a difference.

Right?

Because you want the correct amount of yeast Cells BEFORE you pitch into the five gallons.

The yeast are going to start working really fast, and they're going to try to chew through 5 gallons whether they have enough yeast to do the job or not, and therefore they will be stressed out and produce off flavors.

By growing them in a smaller amount, they will not be stressed out. And you will grow the right amount of yeast.

Also, The biggest reason I suggest folks make a starter is if you make one you'll have peace of mind. It's especially important if you have questionable situation happenning with your yeast, like not being sure the yeast arrived healthy.

And you won't be starting an "is my yeast dead" thread in a couple of days.

Making a starter first insures that your yeast is still alive and viable before you dump it in your beer. You will be less likely to start one of those "is my yeast dead?" threads that are on here every day.

You will also ensure that you have enough yeast usually the tubes and smack packs are a lot less yeast that you really should use for healthy fermentation.

Making a starter also usually means your beer will take off sooner, because the first thing that the little buggers do in the presence of wort (whether in a flask or in a fermenter) is have an orgy to reproduce enough cells to do the job...So it won't take such a long time in the fermenter since they started doing it in the flask.

So making a starter proves your yeast is still healthy, allows you to grow enough yeast to do the job, cuts down on lag time, and ensures that you will not get off flavors or stuck ferementations from stressed out yeast.

Revvy, thanks for the explanation. You bring up some benefits I hadn't thought of. I'm still a little unclear on the reason why the yeast are stressed out though. Wouldn't they just reproduce until there were enough of them to get the job done? Why does it matter that they are reproducing in a starter or in the beer?

proves your yeast is still healthy

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yes this is a benefit, but a swelling smack pack would do the same.

cuts down on lag time

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yes this a big benefit of a starter.

allows you to grow enough yeast to do the job, . . . and ensures that you will not get off flavors or stuck ferementations from stressed out yeast.

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This is what I don't get; won't the yeast just keep reproducing till there are enough of them to do the job?

Sorry if I am being thick.

jingleheimer76 said:

This is what I don't get; won't the yeast just keep reproducing till there are enough of them to do the job?

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No, they will start chewing through the sugars before there are the "proper" amount of cells to do the job via replication.

Think of it like trying to move to a new house. You and a buddy can get the job done, but it will take forever and you'll be whipped by the end of the day. If you get 10 guys to do the same job, you'll progress faster, more efficiently, and you won't be nearly as tired when its done.

There is a considerable body of research out there on pitching rates, including results from experiments where the effects of various rates upon final beer quality were assessed. Google is your friend.

Wyeast's website notes the following potential consequences of underpitching: Excess levels of diacetyl; Increase in higher/fusel alcohol formation; Increase in ester formation; Increase in volatile sulfur compounds; High terminal gravities; Stuck fermentations; Increased risk of infection.

Stuck ferment is the main problem that I used to have before I got more into fermentation and started using starters and pure o2. I kept having beers stall at 1.020 which really should have been around 1.010. Really sucks when you get sweet beer when it's not supposed to be that way.

on your next beer, try pitching once cell of yeast and see what happens

One other benefit - a starter decreases the chance of infection, by giving the pitched yeast a big head start over other bugs. Remember, most of the stuff we do merely sanitizes, not sterilizes.

The way I look at it is what harm does a yeast starter cause? Absolutely none, so why not use them? They're quick and easy to make too.

g-star said:

Think of it like trying to move to a new house. You and a buddy can get the job done, but it will take forever and you'll be whipped by the end of the day. If you get 10 guys to do the same job, you'll progress faster, more efficiently, and you won't be nearly as tired when its done.

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10 guys will drink up all the beer, then you have to start over.

Another reason is:

Yeast can sense there surrounds and realize what they have to do to get the job done. If you pitch to little yeast you will have 15 octo moms in really bad health. Making a starter allows moms the time to make daughter cells, and daughter cells who have more daughters. Instead of throwing 5 moms in and expecting them to divide themselves into oblivion, time allowed by a starter will allow virgin cells to help in the reproducing once you hit your beer with them.

Yeast get scar tissue on their cells walls, the same walls they pass food through. If you introduce them into a medium rich in food and there is not enough of them they will produce until they are battle torn and worn out.

In other words please see exhibit A, I would not want this in my beer.