At Milk Street, we measure flours by weight rather than volume, correcting for scooping irregularities and air that otherwise could throw off our recipes. We wondered whether sugars could benefit from similar treatment.
To find out, we weighed 12 sugars—seven dry and five liquid—60 times each, scooping and leveling for the dry and pouring for the liquids. The results surprised us.
We thought we'd get less variation because sugar—unlike flours—don't trap much air. While that's true, we hadn't accounted for variances in grain size. From brand to brand, even package to package, the size of the sugar granules can vary widely.
This showed up in our test results, where 1 cup of white sugar could weigh as much as 236 grams or as little as 208 grams, even when weighed by the same person.
Brown sugar—both light and dark—was another place where irregularities were glaring. Traditionally, it is measured by packing it tightly into a cup or spoon. But the amount of sugar varied greatly depending on how firmly each person packed it, sometimes measuring 160 grams, others as much as 246 grams.
As expected, liquid sugars didn't give us give nearly as much variation when measured by volume, but weighing them did correct for one persistent problem of working with syrups—stickiness.
Even when we used a rubber spatula to scrape honey, molasses and similar sweeteners out of measuring cups, we never got it all. This meant not all of what we measured ended up in our recipe.
The solution was to set our mixing bowl directly on the scale, zero out the scale, then add the sweetener directly to the other ingredients, no measuring cup needed.
After surveying published sugar weights from a variety of sources and finding as much variation as in our own testing, we arrived at our weights by averaging all of our results.