Starter question

[Rhumbline]

I'm trying to understand starters.

Because I brew mostly big beers, Stouts and RIS's, I've decided I need to study using a starter. I haven't up to now, I typically used multiple packs of yeast.

I see references to one liter, two liter and up to five liter starters. My understanding is that you take a certain amount of wort, add a package of yeast, and let the yeast be fruitful and multiply. You then add the yeast to your actual wort.

So, why couldn't I just dump that pack of yeast into the five gallons of wort? Is it because the yeast would have too much to eat?

 

[Big Monk]

Starters are used to provide an adequate # of healthy cells to ferment the wort

 

[RM-MN]

It takes a certain number of yeast cells to make the best tasting beer. How you get those cells is up to you. You can pitch multiple packs, you can grow more cells from a single pack by making a starter, or you can grow the cells in the fermenter. If you pitch enough that reproduction in the fermenter isn't necessary, you get a certain flavor from your beer but if you want to control the reproduction so that the yeast doesn't multiply in the fermenter you need to make sure of the conditions in the fermenter. Yeast multiply if there is the condition for reproduction. They need free amino nitrogen (which is provided in your wort) and oxygen. No oxygen means no reproduction.

If you provide sufficient oxygen to go along with the free amino nitrogen, a single pack of yeast will reproduce in the fermenter until there is enough yeast or until they use up all the oxygen. If you make a starter you will have more yeast cells going into the fermenter and won't need as much reproduction and less oxygen will be no problem.

There are several yeast starter calculators and the size of starter they say you need will vary. They can't all be right so which is right? Most people recommend that you need a stir plate to make a starter but experimentation by WoodlandBrews says otherwise. http://www.woodlandbrew.com/2015/02/yeast-starters-stirred-vs-not.html

How much yeast is needed is also debated but according to this experiment that amount is only a rough suggestion as you can make acceptable beer with widely varying amounts of yeast. Read through this short article a couple of times, noting well the amounts of yeast pitched into the wort. http://sciencebrewer.com/2012/03/02/pitching-rate-experiment-part-deux-results/

 

[Rhumbline]

It takes a certain number of yeast cells to make the best tasting beer. How you get those cells is up to you. You can pitch multiple packs, you can grow more cells from a single pack by making a starter, or you can grow the cells in the fermenter...

Read through this short article a couple of times, noting well the amounts of yeast pitched into the wort. http://sciencebrewer.com/2012/03/02/pitching-rate-experiment-part-deux-results/

Thanks, your post was just the kind of objective point of view that I was looking for.

I haven't read the linked doc yet, I'll do that in a bit, but thanks again.