Sous Vide Steak temperature issues

Hi @bos, quick question, is the inside of the meat that gray color or just the outside?

The steaks have been between 8mm and 20mm and both times they were grey/brown all the way through.

Unsure as to why it's graying, but some random thoughts:

1. Have you been slicing the steak at all before bagging? Exposure to normal air will turn meat gray, as it's only red when freshly cut.

2. Perhaps it has to do with the salt you've added that's pulling the moisture out?

3. Perhaps something to do with your altitude?

Thanks for your thoughts, here's my responses:

1. The meat has not been sliced after being bought. It's still pink when it goes into the water.

2. I hope not, it's just a few granules. Is this a known thing?

3. I'm at sea level!

I tried again with another 2cm steak today which I cooked for 2 hours at 48C. It came out grey on the outside but lovely and pink inside. However, according to the temp chart I linked to above, it looks more like it's been cooked at about 56C.

What gives!

I know you've already considered it but the only rational answer given the additional information you've provided subsequently is that the temp probe is under reading at 55C.

As noted, the surface of meat turns grey in the presence of air and this effect could explain the greyness of the 8mm thick steak (I'm not really sure as I've not cooked steak that thin) but this would not explain the 20mm.

I don't jaccard meat but if you are doing this process a by-product is that some of the internal muscle is exposed to air but just guessing now.

I was afraid that would be people's conclusion. I'm not sure how that could be the case but what would be the best way of testing whether both my thermometers are calibrated correctly?

It seems that at 48C and 55C both steaks turned grey on the outside but only the 55C steak was grey inside. Could it be something to do with having a poor vacuum when cooking?

I don't tenderise steaks when cooking sous vide.

We've been using one at work for a month or two and it's worked well. One little tic that annoys me is that it displays only Celcius and has no provision for Fahrenheit. Every time Chef asks me about the proper temp I need to dig out a calculator. Aside from that the unit is very solid. It has a strong heater and can circulate 20 gallons of water.

I'd consider buying one myself if I didn't already have two Sous Vide Supremes.

Ooops, sorry! This was meant for a different thread...

I know this is an old thread, and the OP has already done some of this, but for reference, here's how to calibrate (or at least test) your thermometers.

How To Calibrate Cooking Thermometers
http://www.allfoodbusiness.com/calibrating_thermometers.php

Ice Point Method
-Fill an insulated cup with crushed ice and water.
-The cup must have enough crushed ice to provide an environment of 32°F, so you may need to pack more ice into the cup during the process.
-When the mixture of the water has stabilized in about four or five minutes, insert the thermometer to be calibrated to the appropriate immersion depth.
-Be sure to hold the stem of the instrument away from the bottom and sides of the container (preferably one inch) to avoid error.
-If your thermometer is not accurate within +/- 2°F of 32°F., adjust the thermometer accordingly. The ice point method permits calibration to within 0.1°F.

Boiling Point Method
-Place distilled water in a container and heat.
-After the water in the container has reached a complete “rolling” boil, insert the instrument to the appropriate immersion depth.
-Be sure there is at least a two-inch clearance between the stem or sensing element and the bottom and sides of the container.
-If your thermometer is not accurate within +/- 2°F of 212°F., adjust thermometer accordingly. The boiling point method permits calibration to within 1.0°F.

Okay, I've now calibrated my thermometer and also bought a Sous Vide Supreme. Both agree with each other on temp to about 0.5C (is it usual for the SVS to change as much as +-1C while cooking?)

Last night I tried some handmade burgers from shop-bought beef mince. I cooked them at 48C for 45 minutes. They came out soft and tender but, strangely the whole burger (they were about 2" thick) was the same weird grey colour. None of the mince remained pink anywhere in the burger. What could be happening here?

Bos, I've found the same temperature range fluctuation on my SVS which is a bit disappointing as I was hoping for 0.5 or less. I suspect in practice it doesn't make a lot of difference, though I wouldn't use it for very low cooking temps. My circulator set up stays rock solid to 0.1

I'm frankly confused...
when I do burgers (usually about 1") at 134F (56C) for an hour, they are beautifully pink all through.

Tell me about it...

Where do you get your meat from? Is it freshly minced? Is it pink on the outside? How long do you cook for?