sous vide & food safety

[biggreenmatt]

So I bought myself a sous vide unit a month ago and have been playing with it since. Veg, eggs, meat less than 1 lb per pouch & nothing that'd take more than an hour or two, all going into ziplocs. For what I've done so far, food safety issues haven't really surfaced.

Now I wanna make brisket.

I've read up on sous vide safety, know about the "danger zones" and how hours and hours of an internal temp of 135F will kill bacteria just as surely as a second or two at 165F. It's my intention to s.v. my five pounder for two days at 135 to kill off the bacteria and get it nice and tender.

I'd like to hear from anyone who's done long-time sous vide work with big hunks of meat, are familiar with food safety issues (and how to avoid them) and can advise on the difference between ziplocs and vacuum sealing.

Thanks, all!

[Puffin3]

You are probably aware of this site but if not prepare yourself! It's like the 'book' on all things SV. sv
http://forums.egullet.org/topic/13627...

[biggreenmatt]

Yeah, it's pretty sick. Medium-rare and falling apart. Super-ultra tender with a bit of the iron-coppery bloody taste of a good steak.

Would've been better with a good char, but I didn't have the patience.

[biggreenmatt]

Hey, guys.

From my understanding, there's no issue with food safety using ziplocs versus a proper vacuum seal, insofar as it's the temperature of the product that matters. Someone mentioned that the issue is fat oxidizing, which creates a bad taste, supposedly.

In any event, I cut my 5 pounder in half (it was a very small brisket, comprising some flat and some point) and ziploc-ed them individually. Checked them this morning- they were pretty much still tight, but out of an abundance of caution, I re-sealed them again using the water displacement method. Lots of juice in both of them- smelled good but looked a little foul, which is to be expected, I suppose, when you're basically poaching meat in its own juices.

Rather than blowtorch (fun but tedious), I'm just going to throw it on my BGE for a minute or two.

I'll post pics as they come.

[mugen]

egullet is probably the best resource for this - there are extensive discussions of SV, with some participation from Nathan Myhrvold and others.

[sal_acid]

And me! Under a different name.

[GH1618]

Did your sous vide unit come with ordinary ziplocs, or recommend using them?

[ttochow]

It wouldn't really matter since the choice between ziplock and vacuum bags is independent of the SV machine. Sort of like the choice of what material for a braising dish to use in an oven.

That said, the Sous Vide Supreme website has lots of recipes calling for ziplocks sealed with the "Archimedean principle." I have the Polyscience unit, and the recipe book calls for vacuum only.

[GH1618]

It matters only in whether any sous vide manufacturer admits ziplocks which are not vacuum sealed as being acceptable.

[GH1618]

I see. The Sous Vide Supreme site admits the use of ziplocs without vacuum when the pouch contains enough liquid to allow the air to be evacuated by immersion of the pouch in water before sealing. The important thing is to eliminate the air, not to do it by means of a vacuum.

[ttochow]

Yes, I was taking as given sealing with as much air as possible removed. The ziplock method is also suggested in the Modernist Cuisine at Home, but as I recall for only short SV sessions (less than 4 hours?). For longer SV sessions, as I recall, it says vacuum is important. Because I care about safety (food poisoning is god-awful, I've had it not by my hand and thought I'd die), I read and re-read everything. From what I've been able to gather, the advantage of vacuum over the "Archimedean principle" is that more oxygen is removed and there is less fat oxidation over long cooks. I admit I might be wrong.

[Bryan Pepperseed]

I think MC and the "SV pros" suggest vacuum sealing long session items mostly as a "disaster avoidance" measure since it's possible that built up steam in a ziplock can cause the "zipper" to fail - I think some even recommend "double vacuum sealing" as an added precaution to avoid a bag full of water.

[ttochow]

Could be. I am making the carnitas recipe. In the sous vide variation, which cooks for 36 hours, the book states "To avoid off-flavors, do not use a zip-top bag."

Edit: sorry, forgot to mention that recipe is from MC At Home

[Bryan Pepperseed]

Interesting. I don't recall the original MC saying anything about off-flavors, but I probably just missed it.

[biggreenmatt]

Thanks guys- brisket went in this morning with salt, pepper, garlic powder and love. Currently looks gross, but I'm expecting great things on Saturday morning.

Thanks again!

[ttochow]

Please post your results when you have a chance. My longest is about 15 hours with a flank steak at about 132 degrees. Everyone else - who are my reliable critics - really liked the result. Medium rare, and as tender as any filet mignon. Being from Texas, however, I am used to chewy flank, and the texture weirded me out. But it was also my first time to use a blowtorch, and I haven't figured out its secrets. I seem to do much better over a really hot grill using coals from a wood fire.

On the plus side, the blowtorch is excellent for lighting the fire!

And for me, everything that comes out of the SV bag looks like something off a school cafeteria steam table. But it gets pretty after a good sear.

Good luck!

[ttochow]

I am new to this too, so take what I have to say with a grain of salt. And, please, anyone who finds fault in what I have to say, please correct me. I want to learn too.

First, my understanding is that leaching is not a big issue. Here is a link I liked.

http://yourdoctorsorders.com/2012/12/...

Second, my understanding is that the safety issue with ziplock vs vacuum is not an issue. That even vacuum packing leaves a certain amount of oxygen in the bag. I saw this in a Baldwin YouTube video, but do not remember which one.

However, I have Modernist Cuisine at home, and for long term cooks, vacuum is is recommended. Safety was not an issue, IIRC, but taste was. Because of the temperature and the relatively high amount of oxygen, the fats tend to oxidize, producing off-flavors.

I wish that I could say I have direct experience, but my focus has been elsewhere. I can say that chicken breast sous-vide followed by a high-heat mesquite-wood sear was one of the best things I've eaten!

[sal_acid]

I do lots of sv for brisket ...corned beef...pulled pork. It works very well. Safety? Get Douglas baldwins book on sv and check out the tables. It is well worked out, eGullet.org has a huge sv archive well worth browsing too.

Big hunks get up to temp quickly compared to the length of cooking and there's no worry about a big chunk cooked for two days. Short times eg a hour or two are very thickness dependent though.

Ziplock brand bags, the kind without the sliding zipper, are water tight. There's conjecture about the plastic leaching stuff out during cooking. I get no sense of that and use them a lot. Vac sealer bags are cheaper if bought at cabellas and are unquestionably ok with heat. I use them if I plan on cooking and then storing before serving.