Opinions on yeast starter calculators - Home Brew Forums

 Home Brew Forums > Opinions on yeast starter calculators

04-06-2012, 06:33 PM   #1
OvaTersley
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Jan 2012
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Are they accurate?
Which one is best?
Are there (better/alternative) methods of determining starter size?

04-06-2012, 07:14 PM   #2
jww9618

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Jan 2011
Little Elm, Texas
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04-06-2012, 08:14 PM   #3
Polboy

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Jun 2011
Chicago, IL
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i agree on yeastcalc.com i actually did the 3 step starter and counted cells under microscope at the end and results were very close to the calculations from the website

04-10-2012, 12:37 AM   #4
OvaTersley
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Jan 2012
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Quote:
 Originally Posted by Polboy i agree on yeastcalc.com i actually did the 3 step starter and counted cells under microscope at the end and results were very close to the calculations from the website
I'm surprised more people haven't done this. I would love to be able to quantify the numbers from these online calculators with actual cell counts.

Polboy, I'm glad your not just putting blind faith in the numbers, thanks for helping to validate the math.

04-10-2012, 01:54 AM   #5
MrManifesto
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Apr 2011
Brooklyn, NY
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i use http://www.mrmalty.com/

i don't have a microscope but i know it's very popular and a lot of people swear by it.

04-10-2012, 01:59 AM   #6
curtw
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Mar 2012
Santa Clara, CA
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So I'll bite. The questions I have after looking at starter calculators like the one at yeastcalc.com are:

1. How much *water* should I start with to end up with a "X.Y liter" (e.g., 1.5L) starter?

2. How long does it take to to get to the quoted "Total cells at finish"? Oh, on the "Care and Feeding" page it says 24hr @ 70-75F...

3. Given my lack of a kitchen scale :-( , what volume of DME do I need per ounce?

Thanks!

04-10-2012, 04:08 AM   #7
OvaTersley
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Jan 2012
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The DME doesn't displace much water, I think if you add 5.2 ounces of DME to 1.5 liters of water you end up with something like a 1.7-1.8 liter starter.

I'm not really sure how to convert DME weight into DME volume.
You can pick up a digital scale for like \$20, they really are a necessity if you are going to get serious about brewing. Especially if you go all-grain.

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04-10-2012, 08:17 AM   #8
dragonbreath11
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Apr 2011
Linden, New Jersey
Posts: 180
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Quote:
 Originally Posted by curtw So I'll bite. The questions I have after looking at starter calculators like the one at yeastcalc.com are: 1. How much *water* should I start with to end up with a "X.Y liter" (e.g., 1.5L) starter? 2. How long does it take to to get to the quoted "Total cells at finish"? Oh, on the "Care and Feeding" page it says 24hr @ 70-75F... 3. Given my lack of a kitchen scale :-( , what volume of DME do I need per ounce? Thanks!

From the horse's mouth:

http://www.wyeastlab.com/hb_makingastarter.cfm

Starter Cultures – Home Brewers

Making a starter culture to increase the quantity of yeast pitched into a particular beer is a great way to assure consistent results. If you are brewing a high gravity beer (greater than 1.065 original gravity) or a lager that will be fermented cold then you need to increase your pitch rate by pitching more packages of yeast or making a starter culture.

The Wyeast Activator (125 ml) smack-pack is designed to directly inoculate 5 gallons of standard ale wort (O.G. < 1.060, 65-72°F). When brewing high gravity beer (O.G. >1.060) or cold fermented lagers or ales (<65°F)) additional yeast will be required. An Activator contains approximately 100 billion cells which will deliver slightly less than 6 million cells per milliliter in a 5 gallon batch of beer.

Pitch Rates:
For a determination of appropriate pitch rates please see the Pitch Rates section in the Technical Information section of this website.

Once you know how much yeast you need, you can plug the numbers into Wyeast’s Pitch Rate Calculator to determine the size of starter to make.

Cell Growth:
The two main factors associated with controlling the level of cell growth in fermentations are sterol content in cell membranes and amount of sugar available.

In most standard fermentations, the sterol content in the cultures is the limiting factor in cell growth. Sterols (See Oxygenation section) are only synthesized during the early stages of fermentations and are diluted every time a cell buds. When sterol levels reach a certain point in the cell membrane, the cell will stop budding. If very high pitch rates are used, as is the case with most starters, the culture can exhaust the sugar source prior to depleting the sterol contents. The depletion of sugar will cause the culture to stop growing.

Starter Recipe:
The optimal media for cell growth and health require using a malt based media (DME) fortified with nutrients. Gravity should be kept near 1.040 and cultures should be grown at 70°F.

Recipe
0.5 cup DME (100g, 3.5oz)
½ tsp Wyeast Nutrient
1qt.(1L) H2O
Mix DME, nutrient, and water.
Boil 20 minutes to sterilize.
Pour into a sanitized flask or jar with loose lid or foil.
Allow to cool to 70°F.
Shake well and add yeast culture.
Timing of Starter:
Because starters are inoculated at high cell densities, growth is usually maximized within 24-36 hours. The gravity of the starter should always be checked prior to inoculation into wort to assure proper cell growth . Cultures should be used immediately, or refrigerated for up to 1 week before using. Cell viability will decrease rapidly if culture are left at ambient temperatures for extended time.

Stirring and O2:
Agitation aids in removing inhibitive CO2 from suspension as well as possibly adding small amounts of oxygen. Stirring or shaking the starter periodically or using a stir plate will improve cell growth. The use of stir plates has been shown to increase cell growth 25-50% over a non-stirred starter.

Small additions of oxygen periodically throughout the growth of a starter will replenish sterols and improve cell yield.

Caution: It is important to understand that creating a starter can increase the risk of infection by undesirable organisms. Small levels of contamination can multiply to unacceptable levels, causing undesirable effects on the finished product.