Starter - MrMalty vs Beersmith

[Sippin37]

I'm about to make my first starter. I input all the info into both Beersmith and MrMalty but I am getting a different Starter Size Needed. Beersmith is telling me I need 0.40 Liters, and MrMalty is saying I need 1.45 Liters. Can someone take a look at the numbers and let me know why the difference?

Ale
1.067 OG
5 Gallons
1/16/12 Production Date for yeast pack
Growth Factor - Use larger starters, drag all the way to the right (On MrMalty)



Thanks

 

[Nateo]

When I'm trying to figure out how much yeast to use, I like to do my yeast calculations by hand.

How much yeast do we need?

"Standard" pitching rate for ales:
(0.75 million) X (milliliters of wort) X (degrees Plato of the wort) = # of cells we need.

[0.75m = 750,000] x [5gal to ml = 18,927ml] x [Divide SG (67) by 4 to get *P = 16.75]

For your beer, here are the numbers plugged in:

750,000 x 18,927ml x 16.75*P = 237,770,437,500,

Let's round up to 238b cells.

For the next part, we need to figure out how large of a starter we'll need to get 238b cells. For this I'll use White and Zainasheff's book "Yeast" for a table of growth rates per starter volume.

Here's the formula we'll use, where "x" is the amount of yeast we have:
x + x(multiplication factor, or "y") = 238

Our vial should have 100b cells, so that's our "x"

100 + 100(y) = 238
100y = 238-100
100y = 138
y = 1.38

1.38 isn't in the table, but the closest value is 1.45 for a 3L starter.

So if we make a 3L starter, that will give us 245b cells:
100 + 100(1.45) = x
100 + 145 = x
245 = x

When I plugged the same numbers into the MrMalty calculator, it told me we need 231b cells, and we need a 2.6L starter, assuming 100% viability. I'm not really sure how MrMalty came up with those numbers, but there they are.

 

[SkipperNC]

Mr. Malty is Zainasheff's creation for what it's worth. A variable here would be bigger starter, versus more yeast into the starter.

Nateo had all kinds I great advice going on so I would propose going with those numbers.

 

[TipsyDragon]

Mr Malty has lots of settings that affect the starter size. Make sure you are using equivalent settings for both.

 

[Sippin37]

Thanks Nateo. I've looked at all of the settings on both Beersmith and MrMalty, they are still giving me two very different recommendations. I will be using a stirplate so I wonder if that is what is affecting the difference so much. I made sure to select that on both calculators. I think I will just going with MrMalty's calculation on this since I have seen people recommend this more than any other calculator.

thanks guys

 

[iaefebs]

Both MrMalty and BeerSmith agree that you need 231 billion cells. How they get to that number is where the difference in starter size you see. Brad at BeerSmith argues and I will quote


"I know it is probably heresy to say so, but I think BeerSmith might be most accurate here. I've been meaning to talk with Jamil about
this as I think he may be rolling in the stir plate correction factor too late in the calculation:

Here's some of the math:
- About 75 billion cells available from the yeast (based on viability)
- Need 308 billion total for the batch
- Growth factor needed is 308/75 which is 4.1 overall growth factor for the starter
- The stir plate growth multiplier is 2.66 so we get 4.1/2.66 = 1.54 growth needed (equiv without stir plate)
- To get a 1.54 growth factor, you need an innoculation rate of roughly 100 million cells/ml (from a table lookup) - its not a large growth
- Dropping 75 billion cells into 0.81 quarts is 75 billion cells/0.77 liters which is very close to 100 million cells/ml
- So as far as I can see the 0.81 quarts (say round it to a quart overall) is accurate if you have a good stir plate

Honestly I could not match your numbers on Mr Malty without raising the growth factor way up - I think he is calculating the number of packs needed without factoring the stir plate in and then calculating the size of starter needed and factoring the stir plate in here. To my way of thinking, the stir plate is a very important factor when estimating the number of packs of yeast needed, which is why I follow the outlined steps above.

Thanks,
Brad"

This ends Brads quote

I would love to see a response from Jamil...

 

[Sippin37]

Thanks Brad, that is some great info. I was just thinking about this, is it possible that when Beersmith says 0.40 L it is really telling me the amount of actual yeast after decanting the starter?

Being that this is my first starter, is it accurate that you would get 0.40 L of actual yeast after decanting from a 1.45 L starter?

 

[TeeJ911]

Jamil/White say in their book that 1m cells/ml/plato is the rule of thumb for yeast repitched not yeast pitched off packs and propogated. They feel a better rule is .75 mil/ml/plato but again that is for repitched not for properly propogated lab yeast.

I own a nano brewery making 1bbl batches at a time and I am one of those that believe the yeast are the most important part in the beer from selection to health to temp control etc and here is what I have learned. There is a lot of hysteria out there about underpitching and we have swung to the other end of overpitching. Now, some will argue better to overpitch then under and I would agree on most occasions that may be the case but without knowing those occasions you are back to square one.

I will give an example. Our most popular style is our Rua Beoir Irish Red. It is an ale Irish Red but fermented at 65 degrees and Wyeast recommends I pitch a full liter/bbl of their commercial yeast slurry. They guarantee 1.2 billion cells/ml giving you 1.2 trillion cells for a full liter and a pitching rate of 10 mil cells/mil. If pitching on a plato of 10 that will give you 1 mil cells/ml/plato. I use Wyeast 1335 which should finish very clean and dry but with a nice malt profile. I did a test batch to pitch that same exact rate of propogated yeast and what do you know. 15 gallons fermented out completely in 5 days but the true test was to taste it. Sadly it was not what I expected....it was so clean it was bland.....it is a delicate beer to begin with that should be easy to drink but still have a toasty flavor in the middle and a light roast at the end and then a dry finish. This, this was lacking so much of that profile.

I am sorry if this may begin to become long winded but bear w/ me and hopefully I bring it all around full circle. The Rua Beoir recommended pitch rate is the same pitch rate they recommend me for the Pils we make. Their reasoning is because I ferment at the very low end of that ale yeast but the other 2 ales we make they recommend .5 liters of slurry which gives you 600 billion cells/bbl, yes a full .5 mil cells/ml if pitching on a 10 plato. Why?

Let me point you to 'yeast' by Chris and Jamil and on page 122 where they talk about pitch rates. They recommend on ales .75 mil cells/ml/plato for repitching harvested yeast. If you are propogating from a vial/pack, using a stir plate, introducing pure o2 up to 10 ppm and yeast nutrients I have gotten better results w/ .4-.5 mil cells/ml/plato. Of course you have to figure out what works best for your beers.

I highly suggest everyone does some experimenting w/ their starters. There is a very easy way to figure out how much yeast you are pitching by putting gradaution marks on whatever vessel you use to propogate your yeast. Maybe 100ml marks? Make your starter and a day or 2 before brew day stick it in the fridge and let all the yeast drop out. At the bottom you will have a nice layer of yeast solids. Yeast solids are 8 billion/ml in lab yeast so a fair number 6.4 bil/ml assuming 20% is non yeast solids.

Wyeast says 6 million cells/ml up to SG 1.062 on ales and 12 million cell/ml up to SG 1.062 on lagers. Why? Because they are lab yeast primed w/ nutrients and ready to go. My personal experience has shown that if using first generation fresh lab yeast and using good propogation practice a pitch rate of .5 mil/ml/plato is my start point and I will adjust each batch accordingly and I cannot emphasize enough the importance of adding pure o2 to your beer before pitching otherwise all this talk is for not.

To bring it down in size to what the normal home brewer does. Say you want to make 5.5 gals of a 1.053 pale ale. You would need approximately 135.3 billion cells to pitch if pitching .5 mil cell/ml/plato so obviously a smack pack/vial straight off the lab line is still not enough so please make those healthy starters but experiment and keep deligent records of your approximate pitch count and see what works best for each beer you make. The fact is if you are at this point in your brewing hobby and calculating how much yeast you want and how to propogate healthy ones you are ready to move on to varying your pitch rates to suit your beer.

One last word of advice....try so very hard to get as close to you can to 10ppm o2 in your wort before pitching. Besides zinc it is the one thing you can do that will make huge differences in the yeast health and ability to grow and multiply.

Cheers!
TJ

 

[truebe]

Did Mr. Malty ever respond to that? It would be great equipment wise if you actually only needed to make starters a 1/3 of the size.

Wish someone could just do their own lab experiment on a stirring plate, ballpark a growth factor, and decide which calculation is closer.

 

[TeeJ911]

Did Mr. Malty ever respond to that? It would be great equipment wise if you actually only needed to make starters a 1/3 of the size.

Wish someone could just do their own lab experiment on a stirring plate, ballpark a growth factor, and decide which calculation is closer.

I can get ~700 bil cells off a 3L starter on a stirplate, nutrients, and plenty of o2. Mr. Malty says I need ~5L and 2 packs to get the same amount. Not sure of why the differences and I don't have a lab but I know how much yeast solids I have in the end and Jamil says 8 bil cells/ml of yeast solid in his book. I substract 20% for non yeast solids.