Yeast Starter

[Thurstday]

I am going to be brewing a high gravity beer this weekend (my second brew ever), with an original gravity of 1062. Reading in my "How To Brew" book on yeast starters it states that, "For more moderate strength beers (1.060 gravity) a 1 quart starter is sufficient." My two questions are...

1. Is a 1 quart starter mean to use the ratio of [1/2 Cup of DME / 2 Cups Water], until its reached a quart?

**1 cup of DME / 4 cups (1 quart) of water**

2. How does this ratio impact how much yeast is produced or reproduced?

The way I visualize it is, the bigger the surface area or volume, the more area to expand.

Example: If I had a 5 gallon fish tank and added 2 fish (one yeast vial), they could produce up to 100 fish. If I had a 10 gallon tank and added 2 fish (one yeast vial), they could produce up to 1,000 fish. Thats assuming the water volume was filled to the top. How would it differentiate if there were different volumes of water in those same tanks.

Am I on the right track, or completely off? I'm having a difficult time wrapping my head around this.

If there is someone out there who understands my confused madness and able to help me out, that would be great. Thanks guys!

 

[BlueHouseBrewhaus]

Google Mr Malty or YeastCalc. These are both good yeast count calculators. You enter your volume, expected OG and the mfg date of the yeast you are using and it tells you how much yeast you need to grow and how big a starter you need. Your starter SG should be around 1.040. You want the yeast to grow and multiply without much stress. A stir plate is also a worthwhile investment. BTW, you don't do a starter with dry yeast. Cheers.

 

[nettekdl]

With your og and an assumed viability of around 75% you would need a 1 liter starter if you are using a stir plate and around a 2 liter without. To figure dme additions I use the 10 to 1 rule, 10ml water to 1g dme. So for 1L starter you'd need 100g yeast and for 2L youd need 200g

 

[WoodlandBrew]

Yeast growth is directly proportional to the amount of extract consumed. So more DME is more yeast. The amount of water doesn't effect growth directly. (This is called a yield factor and for S. Cerevisiae it's about 0.1 gram of yeast produced for every gram of equivalent sucrose. 1 gram of yeast is about 20 billion cells)

However, the gravity is too high then the alcohol will be a problem. 1 cup of DME in 1 quart of water is probably pushing it.

 

[antony]

+1 to yeastcalc, I use it every time. It's especially useful for stepped starters.

 

[Mexibilly]

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

 

[WoodlandBrew]

If you do use one of the popular calculator mentioned, keep in mind they are designed based on a 9°P (1.035) wort. If you use a gravity that is different you will need to scale your results accordingly.

With this calculator you can see the effect with different gravities:
http://www.woodlandbrew.com/2015/02/starter-calculator.html