The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Calculating the butter fat percentage

FredR's picture

Calculating the butter fat percentage

Can anyone help me in calculating the butter fat percentage in commercial butter offered in supermarkets.  I am looking for an unsalted butter with a high percentage of butterfat - a dry butter.  I checked the facts on the backs of several different supermarket butters and came up with a total fat content of 11gm and a total weight of 14gm in a tablespoon of butter.  If my math (always questionable) is correct that's only 78% fat.  I also thought that in the US butter was required to have 80% BF.  Any help with this would be appreciated. 

blaisepascal's picture

The major difficulty in computing percentages from the figures in the nutritional information label is that the manufacturers are allowed to round, and for small values that can make quite a difference.  The total weight could be anywhere between 13.5g and 14.5g, while the fat content could be between 10.5g and 11.5g.  That means the fat ratio could be anywhere between 73% (10.5g fat in 14.5g butter) and 85% (11.5g fat in 13.5g butter).  That range is very large and not very helpful.

You are right about US butter being required to have 80% BF; Federal law (21 USC 321a to be exact) states that butter is made from milk, cream, or both, with or without common salt, with or without colorants, and containing not less than 80% by weight of milkfat, all tolerances accounted for.

If I had to guess, I'd say that, unless otherwised marked, the butter you get in the store is as close to 80% they can get without risking going under.

amazonium's picture

I use Plugra and I found it at the local health food store, of all places. I know this might sound crazy, but I also have made my own from heavy cream- just put it in the mixer or food processor- easy to do and you can work out most of the liquids, which does give you a 'drier' butter to use when making danishes, etc.