I got a SV wand for X-Mas, so have been doing alot of that this month.

I did a flank steak today, which I cut into 3 parts, 3 bags, and did at 52 Deg C for 4 hours. I then Ice Bath'd all three pieces, and 2 went in the freezer, and one went in the fridge.

For dinner, I pulled the fridge version, and warmed up at 48 Deg C for 30 minutes while preparing Lomo Saltado fixins.

When I was slicing the steak, against the muscle grain, I ran into 2 or 3 small blood spots (bright red pockets in the meat - maybe 1" across and spread across 1" worth of slices. I took them out, but was wondering if anyone knows what they are, and what that means? I've cooked many steaks in my 30+ yeas on this earth, and had never seen that.

Second, follow on question: if I want the other 2 steaks more well done, can I pull from the freezer 90 minutes before another meal, and SV at 54 Deg C, or does "twice cooking" them introduce new problems?

Thanks in advance for your feedback!!!

2 Answers 2


I would think the red pockets are liquefied fat and/or water with red dye in them (and some myoglobin, which is what makes red meat red, but often dye is the bigger reason).

If it's steak from a supermarket, it's probably thoroughly dyed, so maybe some of the dye (or a lot of it!) stuck with the fat. Blood wouldn't be bright red, it would be oxidized and a nice brown/gray (if it were even in the steak - almost no blood remains in a steak, it's not why they're red). If you're used to grilling or similar methods, those would allow the fat (and water) to drip off, while SV won't: you're packing it in a bag and keeping the water and fat inside (that being the point of sous-vide cooking, after all).

  • Thanks @Joe M. This makes sense to me. I usually get my steak from a butcher in the area (San Francisco: Guerra Quality Meats), but there was a sale at Andronico's, so I got the flank steak there. Would the existence of this red spot indicate a quality issue with the meat - or just part of what you get with SV that you don't get with Grilling? Any way to avoid for the future? THANKS!
    – Shamir
    Jan 27, 2015 at 18:04
  • I'm not a SV expert, so I'm not sure - but I think it's not significant.
    – Joe M
    Jan 27, 2015 at 18:08

Flank steak consists of the abdominal muscles, primarily the rectus abdominis muscle. The superior epigastric artery and vein* pass through the muscle. Sometimes, during processing, small clots will form inside the blood vessels which will manifest as blood spots when the muscle is cut perpendicular to grain.

*The drawing linked is of a human, but in this case bovine anatomy is similar.

  • Thank Didgeridrew! What's weird is that I have never seen that before when grilling a Flank Steak. I guess the SV prep left the juice in while grilling lets it out!
    – Shamir
    Jan 27, 2015 at 18:00

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