scaling a recipe correctly

[DaleB]

Hi.

I'm about to brew my first batch in a 34L brewzilla gen 4

I'd like to brew this recipe but will be fermenting in a 19 Corny keg of max yield will be less than the 23 litre recipe.

I'm using the grain bill maker fro Kegland (I'm in australia)
Your recipe is for 23 L, but your keg fermenter holds 19 L.
So we scale all ingredients by:

Scaling Factor =. 19/23 = 0.826

• Every grain amount × 0.826
• Every hop addition × 0.826 (but can also leave at the original amounts)
• Yeast stays the same (still 1 × 11.5 g US-05 packet)
  
  so the original amounts are:
  
  

  4.50 kg	New Zealand - American Ale Malt		37.3	5.28	83.3%
  0.20 kg	German - Carapils		35	1.97	3.7%
  0.20 kg	New Zealand - Wheat Malt		35.4	4.19	3.7%
  0.20 kg	New Zealand - Light Crystal Malt		35.4	83.84	3.7%
  0.20 kg	German - Acidulated Malt		27	7.58	3.7%
  0.10 kg	German - CaraMunich I		34	102.58	1.9%

  
  I have ordered a bill with the following:
  
  
• MILLED Grain Bag
  
  3.72 kg American Ale Malt (2-Row) - Gladfield (NZ)
  0.17 kg Carapils / Carafoam - Weyermann (GER)
  0.17 kg Wheat Malt - Gladfield (NZ)
  0.17 kg Crystal Light (Crystal) - Barrett Burston (AUS)
  0.17 kg Acidulated Malt (Sour Grapes) - Gladfield (NZ)
  0.08 kg Caramunich Type 2 - Weyermann (GER)
  
  Does this look correct?

 

[Donoroto]

It does not look incorrect.

For what it is worth: you can always round up or down a few grams. I’d have ordered 3.75, several 0.2, and a 0.1. And yeast does always stay the same for such a slight reduction.

Brewer’s Friend also has a scaling feature in their recipe builder.

Some say that a pure mathematical scaling does not work well for large changes, like from 20 litres to 2000 litres. It takes some careful thought too.

But for small changes, it is ‘close enough’ and just fine.

 

[J A]

In the recipe builder, input all the ingredients. quantities and volumes, being aware of your profile settings. Once it's all laid out at the 23 liter volume, go to "Recipe Tools" dropdown and select "scale". Inputting the desired volume there will make all volumes and quantities will be corrected for the new yield.

 

[Yooper]

The easiest way to do it is right when you're looking at your recipe. Just click 'tools' and choose 'scale':

You can scale by batch size, or efficiency. You can see with my full volume no sparge, I only got 67.5 efficiency on this, so I can change that if using someone else's recipe and settings, or I can scale my own recipe up or down (or even both!).

 

[DaleB]

Thanks. The scale tool confirmed the AI calculations. Nice piece of mind as I don't really want to trust AI just yet