The FDA, however, says it wants to make sure there is no possibility of contamination of the waste, part of a sweeping modernization of the nation's food supply authorized by Congress. The comment period on the proposed regulation closed Monday; it's not yet clear how many people or organizations submitted comments, but McChesney admitted to being surprised by the volume of outrage over the proposal.
Brewers said slapping new food handling requirements on the grain would be difficult and expensive and might force them to dump billions of pounds of spent grains into landfills.
The Beer Institute, a major trade association for the brewers, reacted with pleasure to news the FDA might issue less burdensome rules.
"We are cautiously optimistic that they are going to amend the rule by summer and do so in a way that we can continue this practice without going through the onerous regulatory process they propose," said Chris Thorne, vice president of communications for the Beer Institute.
Brewers argue there are no documented cases of illness from the use of spent grains. McChesney agreed, but said the regulatory modernization effort is designed to orient the FDA more toward prevention than reacting after a problem occurs.
Just because there has never been a case of illness from the grains, he said, "doesn't mean you couldn't have a problem."
Brewers also argue they should be exempt from FDA regulation of byproducts such as spent grain under the same law that makes finished alcoholic beverages — beer, wine, cider and spirits — exempt from the FDA's normal oversight of food products.
McChesney said the agency had been operating under the assumption that since the grain and other byproducts are not in themselves alcoholic beverages, the FDA has authority to regulate them.
The agency will have its lawyers take a closer look at the industry's argument, he said.
"It's at least worth being considered and responded to," he said.
McChesney said a new version of the regulation would likely make clear simply that byproducts should be handled in a sanitary manner — perhaps setting standards for how long it could remain in storage before shipment to a farm, or requiring that it be transported in containers free from contamination.
Breweries and other manufacturers already must treat their ingredients with care to avoid contamination and spoilage, he said. FDA regulators will look at ways to ease the burden on brewers by allowing them to use existing processes and documentation as evidence of the proper handling of spent grains.
If the FDA regulation does go into effect, it would apply to other alcohol manufacturers and byproducts used for animal feed, including used brewer's yeast, used hops, the ground grains from distilled spirits, and the pulp from apples and pears used to make ciders.
In theory, McChesney said, the rules would also apply to the skins, stems and seeds left over from wine production if it were used as animal feed, but vintners say such material is used as compost in the fields rather than as feed.
The regulation would also apply to other food manufacturers, such as bakers, candy and chip makers, and others who send their irregular or waste foods off to be used as feed, as well as manufacturers who produce commercial pet food.