The USDA, which oversees beef production in the United States, says grass-fed means that “the only source of feed consumed throughout a ruminant’s life, except for milk consumed before weaning, must be grass and forage. The diet must consist exclusively of a diet consisting of grass…Animals must not be fed grains or grain by-products and must have continuous access to pasture during the growing season.”
In other words, grass-fed cows only eat grass. All cows are born grass-fed. Farming methods vary, but generally cows drink milk, eat grass, and live on pasture for the first six months or so of their lives. Then, conventionally raised cows are sent to a feedlot for three to four months (sometimes longer) where they are fed a grain diet, a more economical way to get their cattle to market.
But grass-fed beef, or “grass-finished beef,” also has a fair amount of variation. It turns out definitions of “grass” vary. The best quality grass-fed beef tends to be raised on pasture (ideally organic pasture that’s not sprayed with pesticides), while the more common grass-fed beef you find pre-packaged at your local supermarket is sent to a feedlot and fed grass pellets. The best way to get grass-fed beef that comes from cows that actually eat grass is to get to know your local ranchers and family farms. If you don’t have a local rancher, this guide can help.
What’s the difference?
Generally speaking, grass-fed beef has a complex flavor and is leaner. Individual examples vary greatly. Grass-fed beef has a stronger flavor. Some people dislike it, describing it as “gamey” or “barn-like.” In my experience testing for this guide, and more broadly, it’s a matter of familiarity. As someone who has eaten a lot of grass-fed beef, I find grain-fed beef bland.
Key points about grass-fed beef: Cook time is usually shorter. In my experience, one of the reasons grass-fed beef is said to be tough is because it’s overcooked. Make sure you get a good meat thermometer. I like the Thermapen One ($110), but this cheaper alternative will also do the trick.
One thing worth disputing is the idea that grain-fed beef is more fatty and marbled, and therefore more flavorful. In my experience, this is false. The issue isn’t the grass, it’s the breed of cow. Wagyu is popular because it’s a highly marbled breed. Crowd Cow has a great blog post that explains how factors like breed of cow affect marbling, and how to decipher the USDA’s marbling rating system. My suggestion is to sample grass-fed beef from different origins to get a feel for what it’s like. If you like it, order more. If you don’t, don’t bother.
