Belgian Sugar Percentages: Grist or Fermentables?

[ryannecas]

I'm getting geared up for my first brew, either a Belgian Tripel or Dark Strong Ale. My question is in regard to calculating the percentage of sugar in the brew. Generally, a strong Belgian contains 10-20% sugar, but is that measured in grist weight or in fermentables?

For example, let's say you were brewing a beer and used 9 lbs of pils and 1 lb of table sugar. By grist weight, that's 10% table sugar. However, more than 10% of the carbohydrates in the final wort would be from table sugar.

Which do I go by?

 

[GilaMinumBeer]

I have always figured on 10% of the gravity contribution. Curious on what other have assumed.

 

[devilishprune]

That's what I assumed as well. To me, this puts the sugars from the malt and from cane sugar on more of an "equal footing", since sugar contributes more per pound than malt does (assuming you don't have 100% efficiency).

 

[randomsample]

It's a percentage of your total gravity.

Ingredient Gravity = (% ingredient) * Total Gravity

Then you can get pounds by (Ingredient Gravity)/(Gravity Per Pound or Extract potential)

 

[devilishprune]

It's a percentage of your total gravity.

Ingredient Gravity = (% ingredient) * Total Gravity

Then you can get pounds by (Ingredient Gravity)/(Gravity Per Pound or Extract potential)

That's not totally true, although I agree with you that the commonly held notion refers to the percentage of the total gravity.

Your "ingredient gravity" is assuming that all the ingredients contribute equally to gravity, which isn't true. Sugar contributes 46 ppg, and the dry yield fine grind of Briess 2 row is 37. You won't get 37 points from the 2 row, unless you have 100% efficiency. Thus, if you have a grain bill of 9 lbs 2 row, 1 lb sugar, and the gravity is, say 1.05, the sugar isn't contributing .005, it's contributing .046/5=0.092.

I don't know that I understand the second part of your post.

 

[randomsample]

That's not totally true, although I agree with you that the commonly held notion refers to the percentage of the total gravity.

Your "ingredient gravity" is assuming that all the ingredients contribute equally to gravity, which isn't true. Sugar contributes 46 ppg, and the dry yield fine grind of Briess 2 row is 37. You won't get 37 points from the 2 row, unless you have 100% efficiency. Thus, if you have a grain bill of 9 lbs 2 row, 1 lb sugar, and the gravity is, say 1.05, the sugar isn't contributing .005, it's contributing .046/5=0.092.

I don't know that I understand the second part of your post.

Assuming that the denominator includes efficiency, then my math is fine. Perhaps I should have mentioned this, but when you get around to calculating your gravity per pound of ingredient this will always come up.

From "Designing great beers" p.30:

"Lbs needed = Ingredient Gravity/Gravity per lb. malt. Gravity per pound of malt is, in turn, the product of two factors: (1) mash efficiency ... and (2) a number that represents the ideal, or maximum extract, that might be derived from the particular grain in question...."

Sorry if I was unclear.

 

[devilishprune]

I see what you're saying and it is applicable, but only to malt.

Cane/corn/whatever sugar essentially has an efficiency of 100%, so you can't include it in that calculation.

Thanks for the clarification on the lbs needed part, it makes sense now.

 

[randomsample]

I see what you're saying and it is applicable, but only to malt.

Cane/corn/whatever sugar essentially has an efficiency of 100%, so you can't include it in that calculation.

Thanks for the clarification on the lbs needed part, it makes sense now.

I was typing at work for the first post, so it was hastily done.

For the record you can use the lbs needed stuff for sugars too, you just don't have to do an efficiency calculation (the coefficient is just 1).

Here's a few:

Fermentables, Extract Potential (1 lb/ 1 gal)
------------------------------
Cane Sugar, 1.046
Corn Sugar, 1.037
Dry Extract, 1.045
Honey, 1.030-1.035
Liquid Extract, 1.037-1.039
Maple Syrup, 1.030
Molasses 1.036


So say I want 10% cane sugar in a beer with a target gravity of 200. I just multiply .1*200 = 20 for my ingredient contribution. Then, seeing that cane sugar contributes 46 gravity points, I just divide 20/46 to get 0.44 lb

If I was adding 90% pale malt with an extract potential of 1.036, assuming I have a 70% efficient system I can expect a gravity contribution of 25.2 points (36*0.7), so (0.9 * 200) / 25 gives me 7.2 pounds.