Pitching rates and BeerSmith

[philm00x]

I'm building a recipe on BeerSmith that will be using harvested yeast. I'm trying to calculate how big a starter I would need to make, but there's a discrepancy that I can't wrap my head around. It's telling me how many viable cells I need to pitch, and it calculates viability based on harvest date, and suggests how big a starter to make. When I mark the check box for using a stir plate, inputting the suggested starter size yields the amount of viable cells needed to pitch. When I leave the box unchecked (since I don't own a stir plate), inputting the new suggested starter size yields an amount of cells much lower than the amount necessary to pitch. Why is this happening?

[Inkleg]

A stir plate keeps the yeast moving and brings oxygen into the wort. Makes for a better yeast building party over just swirling the jug every time you walk by.

[Kealia]

Yep. Basically, a stir plate grows your yeast more than a starter without one. So if you calculate the numbers using a stir plate and it says to use a 1L starter (for example), then you put a 1L starter into the calculator and it shows fewer cells than it did before, that is why.

Does that make sense? I read it back and I think I'm not wording it well but I tried to paraphrase what you said you were doing.

[philm00x]

Well I understand that a stir plate will allow for faster growth than no stir plate, but I'm trying to figure out why inputting the recommended starter size without a stir plate doesn't add up to match the number of cells. The particular recipe I'm building, it's saying I need 183 billion cells. With a stir plate, it recommends 0.88L starter to make 182 billion cells. Without a stir plate, it recommends a 1.32L starter to make 126 billion cells (nowhere close to the 183 billion it says is required for proper pitch rate). That discrepancy is what I'm wondering about. By just plugging in numbers, it says I would really need to make a 2.8L starter to make 182 billion cells.

[Kealia]

Can you provide the #'s from your recipe? OG, batch size, date of yeast, etc.?

I'll plug in and see what I get so I can try and replicate.

[philm00x]

BeerSmith 2 Recipe Printout - http://www.beersmith.com
Recipe: Saint Sebastian Tripel
Brewer: Mr. Rufus Brewing Co.
Asst Brewer:
Style: Belgian Tripel
TYPE: All Grain
Taste: (30.0)

Recipe Specifications
--------------------------
Boil Size: 2.41 gal
Post Boil Volume: 2.08 gal
Batch Size (fermenter): 2.50 gal
Bottling Volume: 2.25 gal
Estimated OG: 1.081 SG
Estimated Color: 6.1 SRM
Estimated IBU: 30.6 IBUs
Brewhouse Efficiency: 72.00 %
Est Mash Efficiency: 72.0 %
Boil Time: 90 Minutes

Ingredients:
------------
Amt Name Type # %/IBU
3 lbs 8.0 oz Pilsner (2 Row) Bel (2.0 SRM) Grain 1 50.0 %
1 lbs 12.0 oz Pale Malt (2 Row) Bel (3.0 SRM) Grain 2 25.0 %
8.0 oz Cara-Pils/Dextrine (2.0 SRM) Grain 3 7.1 %
4.0 oz Caramel/Crystal Malt - 20L (20.0 SRM) Grain 4 3.6 %
0.90 oz Styrian Goldings [5.40 %] - Boil 70.0 mi Hop 5 28.0 IBUs
1 lbs Sugar, Table (Sucrose) [Boil for 10 min] Sugar 6 14.3 %
0.50 oz Spalter [4.50 %] - Boil 5.0 min Hop 7 2.5 IBUs
1.0 pkg Belgian Ardennes (Wyeast Labs #3522) [12 Yeast 8 -


Mash Schedule: Single Infusion, Light Body, Batch Sparge
Total Grain Weight: 7 lbs
----------------------------
Name Description Step Temperat Step Time
Mash In Add 7.50 qt of water at 163.6 F 151.0 F 90 min

Sparge: Batch sparge with 2 steps (Drain mash tun, , 1.25gal) of 168.0 F water
Notes:

Yeast was harvested 8-4-13

[Kealia]

For a 2.5G volume of 1.081 OG wort I show that you need 136B cells.
If I check the box for stirplate it changes to 137.7 (which is a bit odd that it changes at all, really).

Without a stirplate I show needing a 1.7L starter with 0.38L of slurry, harvested from 8/4/13 with a viability of ~17% at this point.
Does that match what you get?

FWIW, I double checked the numbers at Mr Malty and also came up with 138B needed there.
At the basic settings, it shows 636ml of yeast slurry needed (no starter). I'm not exactly sure how to calculate the slurry with a starter at Mr Malty.

Not sure if any of this helps...

[rickbray66]

Phil,

Are you using the "Yeast Starter Tool" or the "Starter" tab within a recipe. It seems they work a bit different, whereas the "Starter" tab wants to know (record) what starter was actually used, whereas the tool helps you determine what size starter you should use.


Rick

[philm00x]

I've been using the Starter tab within the recipe. Didn't even realize there was a Yeast Starter Tool. Using that, I need 0.38L of slurry for 137 billion cells, so my starter will need to be 1.7L. Thanks for that tidbit, Rick! I'll be using that from now on. Those numbers agree with Mr. Malty's yeast starter calculator, so that makes me feel like it's accurate. Also, thanks Kealia for confirming! I appreciate the help.

[Rebel_B]

BeerSmith 2 Recipe Printout - http://www.beersmith.com
Recipe: Saint Sebastian Tripel
Brewer: Mr. Rufus Brewing Co.
Asst Brewer:
Style: Belgian Tripel
TYPE: All Grain
Taste: (30.0)

Recipe Specifications
--------------------------
Boil Size: 2.41 gal
Post Boil Volume: 2.08 gal
Batch Size (fermenter): 2.50 gal
Bottling Volume: 2.25 gal
Estimated OG: 1.081 SG
Estimated Color: 6.1 SRM
Estimated IBU: 30.6 IBUs
Brewhouse Efficiency: 72.00 %
Est Mash Efficiency: 72.0 %
Boil Time: 90 Minutes

Ingredients:
------------
Amt Name Type # %/IBU
3 lbs 8.0 oz Pilsner (2 Row) Bel (2.0 SRM) Grain 1 50.0 %
1 lbs 12.0 oz Pale Malt (2 Row) Bel (3.0 SRM) Grain 2 25.0 %
8.0 oz Cara-Pils/Dextrine (2.0 SRM) Grain 3 7.1 %
4.0 oz Caramel/Crystal Malt - 20L (20.0 SRM) Grain 4 3.6 %
0.90 oz Styrian Goldings [5.40 %] - Boil 70.0 mi Hop 5 28.0 IBUs
1 lbs Sugar, Table (Sucrose) [Boil for 10 min] Sugar 6 14.3 %
0.50 oz Spalter [4.50 %] - Boil 5.0 min Hop 7 2.5 IBUs
1.0 pkg Belgian Ardennes (Wyeast Labs #3522) [12 Yeast 8 -


Mash Schedule: Single Infusion, Light Body, Batch Sparge
Total Grain Weight: 7 lbs
----------------------------
Name Description Step Temperat Step Time
Mash In Add 7.50 qt of water at 163.6 F 151.0 F 90 min

Sparge: Batch sparge with 2 steps (Drain mash tun, , 1.25gal) of 168.0 F water
Notes:

Yeast was harvested 8-4-13

That looks rather good... A good Trippel will become a regular recipe in your rotation I would think.

[philm00x]

I started the first starter with the Ardennes yeast on Sunday, with 350 mL. Yesterday I made new wort and pitched the first starter into it, stepping it up to a total volume of 1000 mL. The banana and apple esters emanating from the bottle are just amazing. This is definitely the type of flavor and aroma I want the yeast to impart in the Tripel, so I think I'm on the right path.

Just before leaving for the airport, I'll put this in the fridge to sleep so that when I get back, I can bring it back to room temp and let it continue doing its thing. Would pitching it into the Tripel while the starter is still fermenting advisable, or should I let it finish before pitching?

[philm00x]

I pulled my starter out of the fridge last night. As it has warmed up to room temp, I see it's still fermenting. There's maybe 750 mL to 1 L worth of wort and yeast in the bottle (I used an old soda bottle since I don't have a flask big enough). Should I pitch the whole thing even while it's still fermenting the starter wort? Or should I let it finish fermenting before pitching (at which point I could decant the beer).