Internal Temp LOWER than Circulation water Temp

Hey everyone :smiley:

First time posting on this forum.

I have a reoccurring problem with my chicken breast internal temperature always being 1-1.5 degrees Celsius lower than the temperature of the circulating water even after 100 minutes of cooking time at 62 C (breast thickness < 1 inch).

disregarding the temperature I have set on the sous vide machine, I use a food thermometer to measure the temperature of the circulating water which comes to:

  • 61 C

However sticking the food thermometer into the chicken breast (still in the vacuum bag) ) immediately after i pull it out of the water bath the food thermometer reads:

  • 59-59.5 C

This is quite concerning to me as the difference of 1-2 C is quite a big factor when cooking at such low temps.
(and please don’t tell me just to increase the temperature i’m cooking at, i have my reasons :smile: ).

I have also tried using a laser thermometer, however that doesn’t help either (seems to be less accurate).

Does any else have this problem?

Thanks guys!

Hey and welcome Derrek, i have consistently experienced similar negative endpoint temperature variances when i cared to check, though about half yours. Are you cooking frozen product? I never really considered being aware of the variances to be much of a problem

Thermal conductivity or diffusivity in food is dependant on a variety of variable factors and as you discovered partially explains why you can never overcook food using SV. It also appears we can never quite achieve that last half degree or so and i have accepted that without undue anxiety. Consistently being close enough is good enough for me.

As you discovered laser thermometers aren’t much of a benefit as they only measure surface temperatures which we already pretty well know from our water temperature set points, or thereabouts.

Of course there’s another factor to consider. Your water bath is always giving off heat energy as it circulates so it will always be slightly below your Anova’s temperature setting which is being measured inside the circulator.

Just a thought… A check of the temperature quickly made after pulling the chicken out of the bath is still…a check after it is out of the bath. While it does seem like it should hold the temp for at least a bit, maybe you could tweak your temp check just a bit to be even more sure…
Using a ziploc bag, cook the chicken per usual, then open the ziploc without removing the chicken from the bath. While keeping the chicken submerged, through the open top of the bag place the temperature probe into the center of the chicken. Since the chicken will still be submerged this will remove the possibility that you are getting a temperature drop after the chicken has been taken out.

Good luck, and post your results if you decide to try this!

Folks, core temp holds long enough to check even in chix but will never quite match set point targets. Over time temp gets closer and eventually close enough. There’s always a bit of thermal resistance.

Thanks for the reply guys!! really helpful community!

I was thinking about the thermal resistance as well as to chicken with water which is a liquid, but it never fully made sense to me.

i think ill just raise the temp by 1 degree just to be on the safe side

You’re welcome Derrek. A lot of people don’t realize there’s a substantial difference using low temperature liquid water as a cooking medium, not you. More importantly, they don’t seem particularly interested in understanding the difference.

You’re already safe. One degree isn’t going to make any significant difference in Pasteurization as long as you adhere to your practice of 100 minutes at 62ᴼC or 63ᴼC with chicken breasts an inch or less thick. Food safety depends on time and temperature.