I’m always looking for short cuts in cooking. I recently bought a Nomiku consumer sous-vide immersion heater. I have been pretty happy with the low-cost Ziploc-brand vacuum bags and manual pump. I don’t really see a compelling reason to buy a $150 vacuum sealer.
However, a lot of cuts of meat come already vacuum packed in a low-density polyethylene (LDPE) wrapper. Can you just cook the meat as-is in that wrapper as it comes from the store. That would sure make things easy. The short answer is yes. I have now done this a dozen or so times with skirt steak, flat-iron steak, and today with a leg of lamb (for Easter).
There is one objection people tend to have. Aren’t you going to leach some nasty chemical from the bag as you immerse it in the water bath. Short answer: no. LDPE is quite inert. There is nothing to leach, especially at 140F. Secondly, the sous vide bags are also LDPE, so you can’t avoid it. Third, the meat has been in that LDPE bag for possibly weeks. If something is going to leach, it has leached. (Yes, of course the leaching would occur more rapidly at higher temperatures, but it’s only at those higher temperatures for a few hours, compared to many days in storage and transport.)
As far as I can tell, the only real downside is that you can not season the meat in the bag before cooking. However for a thick cut, that seasoning is never going to make it far into the meat anyway. So, you are going to want to use a sauce to impart flavor.
Here is the lamb adventure (so easy).
Buy a leg of lamb that is vacuum sealed. Mine was a 6 lb. Australian leg bought from the grocery store (the New Zealand and Australian products are a little smaller and a little less expensive than the U.S. products).
Cook it sous vide for at least 11 hours at a temperature of 140F. You’re going to need longer for a bigger piece of meat. It takes 10-12 hours for a roast this size to reach the target temperature sous vide. I found the 140F perfect. I can imagine some people wanting it slightly more pink, maybe 136F. I don’t think you should go lower however — the fat doesn’t really melt very nicely. I was really happy at 140F.
Take it out of the sous vide bag and put it on a rack in a roasting pan. I like to put foil under it to make the clean-up easier.
Crank your oven up all the way (mine goes to 500F plus). Dry the roast with paper towels. Pop it in the oven for 10 minutes or until your smoke alarm goes off. This is to give you a perfect golden skin.
Then, let it rest 10 minutes, carve, and eat. This was a little more pink than is evident from the photo. It was really perfect.
My family really enjoyed it with the Bandar sauces (created by a couple of my Wharton innovation students) — the Mint Cilantro worked perfectly.