Liquid Yeast

[jduffell]

Hi, thanks in advance for help.

I have been homebrewing obsessively for only 4 months so please excuse the stupid questions.

I feel like I am ready to try liquid yeast but despite books, videos, and online research I am struggling to understand the use of a starter. I have starter wort to use and I have a vial of yeast. I have watched videos on how to do it and it seems straight forward. Here are my questions:

1. The vial of yeast i have per the manufacturer has ~80 billion cells. I found a yeast calculator that says my recipe requires 135 billion.
How do I know how many cells my yeast starter will produce ?
If there are too many will it affect the taste of my beer?
Are there any methods to calculating # of cells in a yeast?

2. In a recipe there are starter directions that say "250ml -> 1000ml -> decant -> 1000ml" What does that mean? (In the videos I have watched it just says to add wort to the yeast, stir plate for two days, cold crash, pitch)

Thank you!!!

 

[ballsy]

How do I know how many cells my yeast starter will produce ?
As far as I know, theres no way to knoe for sure.

If there are too many will it affect the taste of my beer?
Over pitching can be counterproductive but you would need to over pitch a ton so I wouldn't worry too much about it.

2. In a recipe there are starter directions that say "250ml -> 1000ml -> decant -> 1000ml" What does that mean? (In the videos I have watched it just says to add wort to the yeast, stir plate for two days, cold crash, pitch)
Cold crashing will get all the yeast to settle on the bottom, decanting means pouring off most of the liquid above the settled yeast carefully so as not to disturb the settled yeast leaving a little fluid left over to swirl and produce a "slurry" which is what you add to the Wort.

Check out this link, it's a good way to estimate pitching rates. Also their main website lists a good way of estimating depending on if you do a 1L or 2L starter re: approx. amount of yeast cells.
http://www.mrmalty.com/calc/calc.html

 

[flars]

Here are a couple of other pitch rate/starter calculators that are easy to use for doing starters in steps to avoid one large volume starter.

This one has a overbuild calculator for saving fresh yeast for the next starter.
http://www.brewunited.com/yeast_calculator.php

http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/

 

[frazier]

OK this is just me, but ... this topic can be waaayyyy overthought. I'm a big fan of the KISS approach.

For ordinary beers with a starting gravity up to about 1.055, I make a 2 qt. starter. Bigger beers, I make a 3 qt. starter. Lagers. I make 1 gallon starters.

I aim for the starter having a gravity of about 1.035. Pitch the yeast, shake it if you can, wait 2 days, cold crash, decant and pitch. It really doesn't need to be more complicated than that. If you WANT to spend on a stirplate, or talk about billions of cells, go for it.

Cheers,

 

[Hoofer]

Agreed, dont over think it unless you want to. Yes you can approximate propagation by calculating yeild factors. But really the work has been already done by yeast manufacturers. I just keep it simple. Figure a liquid yeast contains 100b cells. If you want to double just pitch it into a prepared 2liter starter with 200g of dme. Get your temps right and oxygenate. If you dont need to double just reduce the starter size. If you need to do more than double just increase starter size or do a stepped starter.