The golden rules for cooking grass fed and finished beef are — don’t overcook it and don’t ever use a microwave!
1) Since grass finished meat has less fat than feedlot beef, it’s more solid and will cook faster. You will likely need to cut back the cooking time or reduce the cooking temperature from what you may have done in the past with supermarket meats.
2) Avoid using salty or soy based liquid marinades since salt tends to draw the juices out of meat. It’s better to use spice rubs or marinades that are oil and herb based. If you want to add salt, do it at the last minute, or in the pan while cooking.
3) You may also try to adapt your taste preference a bit, in terms of doneness. This is a different product. Cooking to a lower internal temperature results in juicier meat, and it’s healthier for you. Charred meat is never recommended, and meats from grass fed animals are much less likely to have hazardous bacteria that you need to incinerate! Don’t overcook it.
4) So, if you’re a “medium” person, try it a bit rarer than you would normally. But if you insist on having your meat well done, then add some marinade to keep the surface moist and cook as slowly as possible. If you’re cooking on the grill, use indirect heat to finish the cooking process, rather than cooking over the flame. That’s a good approach in general, but especially if you’re looking to cook it medium to well done.
5) No matter how you cook, it’s best to use a meat thermometer so you can consistently cook it the way you like it. Then let the beef sit covered in a warm place for 5 minutes after removing it from the heat to let the juices redistribute.
Overall, once the meat is sealed, slow, low temperature cooking is a great approach for cooking all naturally raised meats. And that brings us to…