Yeast starter

[Firestorm159]

Brewing a 1.080 Wookey Jack clone making a 2 liter starter will it be enough?

 

[jakenbacon]

http://www.mrmalty.com/calc/calc.html

 

[Hex23]

http://www.yeastcalculator.com/

http://www.mrmalty.com/calc/calc.html

 

[Firestorm159]

OK a pack of yeast has 100 billion yeast cells if I do a 2 liter starter 1300ml water and a cup of dme does that double the amount of cells?

 

[jakenbacon]

No I dont think so. Looks like you need closer to 300 for 5 gallons. Dry yeast pack should have more than a 100 though I believe. Mrmalty is saying 1.3 packs, so if you have a standard 200 bill pack, then a simple starter should do fine. What yeast you using with only a 100 bill? or is it just old?

 

[Hex23]

OK a pack of yeast has 100 billion yeast cells if I do a 2 liter starter 1300ml water and a cup of dme does that double the amount of cells?

The point of linking to those calculators is partly to highlight that there are many other variables one should take into consideration: batch volume, date of yeast mfg, starter method (constantly aerated, stirred, intermittently shaken, etc.)

If you want a 2 liter starter, that's really referring to the water volume, not total volume. Dissolved DME is not doing to consume much space.

If you tell us more about your situation, we could probably help by giving an example (screenshot) of how the calculator works.

 

[Firestorm159]

Wyeast 1968 London ESB 100 billion yeast cells. I made a 2000 ml starter just wondering if that would be enough or am I going to have to crash it and do it again. I still don't quite understand how to get a specific number of yeast cells. So I started with 100 billion yeast cells and made a 2000ml starter how does that effect my cell count? Mr. malty say I need 301 billion cells I'll be pitching on around 5.5 gallons

 

[YeastMode]

What yeast are you using? Assuming you are using a a liquid yeast that is fairly fresh and healthy and has a decent attenuation in a 5 gallon batch you should be ok, but you will probably be a bit under by calculation.

FWIW, I pitched two rehydrated packs of BRY-97 in my 5 gallon batch of WJ clone and it was fine.

EDIT: you posted the yeast while I was typing.

 

[Hex23]

Wyeast 1968 London ESB 100 billion yeast cells. I made a 2000 ml starter just wondering if that would be enough or am I going to have to crash it and do it again. I still don't quite understand how to get a specific number of yeast cells. So I started with 100 billion yeast cells and made a 2000ml starter how does that effect my cell count? Mr. malty say I need 301 billion cells I'll be pitching on around 5.5 gallons

Just to illustrate how much the method matters ... With your parameters and a simple (i.e. still) starter, Mr. Malty says you can do a 2L starter with 2 packs, or a 5L starter with 1 pack. But if you have a stir-plate, you can get away with just one pack and a 2 liter starter. Now, this is all assuming the highest initial viability (96%). E.g. if you plugin a mfg date about 2 months ago, then you really only started with about 50 billion cells (~50% viability), and that assumes the yeast was well stored in that two months. Remember these are all just estimates with probably plenty of error, but it doesn't hurt to get in the right ballpark.

 

[Firestorm159]

ok does 2 liter refer to the amount of water you use? I basically used 1300 ml which is a little over a liter of water and a cup of dme. Is that considered a 1 liter starter?

 

[Hex23]

ok does 2 liter refer to the amount of water you use? I basically used 1300 ml which is a little over a liter of water and a cup of dme. Is that considered a 1 liter starter?

Yes, the size of the starter refers to how much water you started with. DME itself doesn't affect the volume much, and calculators are often built to use a PPG (points per pound per gallon) scale. So they are built to assume you added X lbs or DME to Y gallons of water.

Starters needn't be whole liters. The numbers I used above are rounded, since Mr. Malty happened to calculate numbers that were pretty close to whole liters. So, your stater is 1.3 liters and by my estimations about 1.046. That a little high for a starter gravity, but not too far off. Starters should normally be between 1.030 to 1.040.

The other calculator at http://www.yeastcalculator.com/ is nice too since it has a calculator for the starter ingredients.

 

[Hex23]

I assume you may have forgotten the mfg date of your yeast (already threw out the pack). Probably not bad to just assume it's about 4 weeks old (75% viable). The other nice thing about yeastcalculator is that you can also plug in numbers to estimate your cell growth, instead of it just telling you how big of a starter to build. Depending on your starter method and which growth model you trust, you could have between about 146 and 303 Billion cells.

 

[Roadie]

I'm probably overly anal about my starters but i go by water in ml and DME in grams and it's an easy calculation by dropping the last number. 1300 ml would be 130 grams of DME; 2000 ml of water would be 200 grams of DME, etc.

As others have said your method of aeration matters. I make my starters on a stir plate and thus get more yeast cells than I would by doing a simple shake every once in a while method. After fully fermented in 18 - 24 hours I cold crash the starter overnight in the fridge. I take out of fridge and let warm up to pitching temperature then decant the beer just leaving enough to mix the yeast up prior to pitching to make it easier to pour in.

 

[Firestorm159]

Thanks for your help.

 

[WoodlandBrew]

Biomass yield is a function of extract consumed. So when you hear "2L starter" think 200g of DME. The amount of extract is much more important than the volume of water. (Although you do need to make sure the gravity is not outlandish)

Whether you are using a stir plate or not have very little effect on biomass yield in my experience, but it does effect the growth rate. See the PDF at the bottom here:
http://www.woodlandbrew.com/2015/01/cell-density-meter-update.html