Low-temp mash versus adding sugar

[benbrew]

I’ve been wondering about the whole high-versus-low temperature mash thing. Specifically, if a low-temperature mash gives more fermentables, then why not save grain (and money) by doing a high-temperature mash with less grain and adding sugar for fermentables?

Let’s work with some numbers, which I will pull out of my a$$. First, let’s assume you get 30 points per pound per gallon (PPG) from your grain. Let’s also say that you pay $1 per pound for grain. I’ve read that sugar gives 46 PPG. Let’s say that you pay 30 cents per pound for sugar at your local supermarket.

Say you want to make a 10-gallon batch of 60-gravity (i.e., 1.060) beer. This means that we need 60 * 10 = 600 total gallon-points (GPs).

Scenario 1: We use 20 pounds of grain (20 pounds * 30 PPG = 600 GPs) and mash at 149 degrees. Total fermentable cost: $20.

Scenario 2: We use 16 pounds of grain (16 pounds * 30 PPG = 480 GPs) and mash at 158 degrees, then add 2.6 pounds of sugar (2.6 pounds * 46 PPG = 120 GPs, which will bring our total to 600 GPs) to the boil. Total fermentable cost: $16.78.

Obviously there are some questions such as how much fermentability difference is there between a 158-degree mash and a 149-degree mash? How can we know the proper grain/sugar ratio? But you see my point: why use expensive grain to produce fermentables that can be gotten from cheap sugar?

Then there’s the issue of what kind of fermentables we get from grain versus sugar. Table sugar is sucrose, while the fermentable sugar we get from malt is mainly maltose. Do these fermentables produce different flavors in our beer? Is maltose 100% fermentable, the way sucrose is?

Cheers, and happy brewing!

[Vienna Lager]

In answer to the second from the last question:

You will get different flavors in a beer that was made will all malt as compared to one that had table sugar substituted for a portion of the malt. The higher the % of sugar over malt the more noticeable the difference.

The same holds true for any beer made with adjuncts namely rice, corn/maize, and table sugar. Any adjunct will impart a flavor characteristic to the beer as would brewing with rye, wheat or oats.

[corkybstewart]

Your second scenario works well for a lot of Belgian beer styles when you want to end up with a very light bodied, dry(unsweet) flavor.
But if you want a full bodied beer like a stout you should stick with Scenario 1. My wife and I really don't like thin beer at all so most of my beers are mashed around 156 and contain 0 adjunct sugars. The only exceptions are my Belgians, and even there I don't use more than 10% adjunct.
I'm not sure but I'm going to guess that maltose is not 100% fermentable, at least not by normal brewing yeast, whereas sucrose is.
When I started brewing in 1993 the LHBS I bought my stuff from suggested 1 can of extract and 1.5 pounds of corn sugar. Later when I wanted to drop the sugar and use more extract he tried to talk me out of it on the basis of cost, not flavor. So here's my suggestion. If cost is critical use more sugar. If flavor(including texture and mouthfeel) is more critical use less sugar, if any, but always depending on the style.

[beerking]

Since the question was posted on BURPlist as well, I will give the response I gave there:
Sounds like the kind of calculations a big brewery might use to justify brewing Bud Light instead of real beer! :D