Grass fed beef: cook sous vide?

[rotuts]

at todays farmers market I scored some sirloin steaks. grass fed 100%

I was lucky to get them they are not as thick as Id like, but you take what you get. these were pretty much a 3/4 " sirloin cut into two steaks then vac'd and frozen

ive only tried grass fed beef once before and it was so-so on the grill

Id like to SV these.

Ill open the packs and put some rub on them, then reseal and leave to thaw in the coldest part of the frig for a day.

Id like to SV very much on the rare side, but long enough for tenderness. I know there is some risk but 130 might be a little over done, the temp I usually use for super-market meat

how long does it take SV grass-fed for tenderness? 3/4 "

many thanks!

[rotuts]

those steaks might be closer to 1/2 "

thanks

[KennethT]

I've found that the issue with grass-fed is not really in the cooking, but in how the animal was raised, and its condition at slaughter time. It's rare to find (especially in the US) but you can actually get some grass fed beef that has some marbling. I read a whole article once that was interviewing a grass fed farmer well known for the quality/flavor of his beef, and he went on a whole diatribe about how most grass fed farmers will slaughter the cows when they're not mature enough, and haven't accumulated enough meat/fat. This beef winds up dry and tough. He showed pictures of two cows the same age - one ready for slaughter, the other in his opinion required at least 6 more months. He pointed to specific spots on the animal as to where to check for "meatiness". But, he said, most farmers just go by age, and not by development. Plus, it's more expensive to wait longer for the cow to mature.

Unfortunately, this doesn't answer your question. Personally, I'd cook it in a 130/131 bath straight from frozen - it'll defrost much quicker than in the fridge, unless you wanted to jaccard it. McGee recently put out an article where he compared defrosting techniques, and found that defrosting in circulating warm water was best (by far) both from time and quality standpoint. While some people may talk about the bacterial safety of defrosting in 110F water, he said that it defrosts so fast (20-30 minutes) that it doesn't leave much time for multiplication, especially if you'll be cooking it right away. Since you're cooking in a 131 (pasteurizing) bath, you'll kill anything that multiplying if you leave it there long enough. According to Modernist Cuisine, using a 131 bath (which cooks to a core temp of 129), you need to hold for 2h17m once core temp is reached to pasteurize. I don't know how much longer I'd hold it than that, since sirloin is pretty lean (especially grass fed), and I think it would dry out if held too long... so maybe 4 hours at the most?

A great thing to do would be to portion the meat into several portions, and cook in separate bags for different amounts of time. Then you can report your findings!!!

[rotuts]

thats a great tip. since the total weight is about 1.5 lbs I could re-bag them while frozen into 4 'cuts' and go from there.

Id really like to get a lower temp that 130, but its only (soon to be) 4 pieces.

[OliverB]

I just cooked some free range grass fed water buffalo sirloin steaks SV, at 134 for about 2hrs. They were not frozen, I defrosted them in cold water, added s&p and sealed them in new bags. Gave them a very quick very hot (cast iron pan at about 600 degree F) sear and they turned out fantastic! They were also extremely lean and it's easy to overdo it with this kind of meat on the grill, but with SV that was not a problem. Most amazing beef (if you want to call it that) I've had in a long time. Silky and tender, awesome beef flavor, just a complete success. Rosy, on the rare side of med/rare.

Have fun and enjoy!