Cooking sous-vide can be confusing, as recommendations for time and temperature can vary considerably. Personal preference plays a role in this, as well as misconceptions about food safety (i.e. using higher temperatures than necessary). For pork belly I’ve seen recommendations ranging from 7 to 48 hours for time, and 57C/135F to 80C/176F for temperature. I cut a slab of pork belly into 8 pieces, and tried 8 different time and temperature combinations from various sources. None of them came out terrible, but some were clearly much better than others. I will describe them in order of temperature, and end with a conclusion. I would have to do more experiments to come up with the ‘ultimate’ time and temperature combination, but I’m very satisfied with the two best ones.
Here are the 8 pieces of pork belly with supporting ingredients. As you can see it was a relatively lean slab of pork belly, which makes it more prone to dryness.
For about 1.8 kilos (4 lbs) of pork belly I used 1 Tbsp (22 grams) salt, 1 Tbsp ground fennel seed, 1/2 Tbsp freshly ground black pepper, and 1/2 Tbsp garlic powder.
I mixed salt and spices in a small bowl, and spread this rub evenly on all sides of the pieces of pork belly.
Then I vacuum sealed them and labeled them with the various time and temperature combinations I wanted to try.
The piece to be cooked at 57C/135F needed to be submerged in hot water for 10-20 seconds after vacuum sealing to kill any lactobacillus on the surface of the meat. The water needs to be at least 77C/170F. This procedure is required to prevent a bad smell when cooking below 60C/140F.
After cooking sous-vide, I seared the pork belly in a very hot frying pan with just a bit of oil.
I reduced the bag juices and served them alongside.
57C/135F for 48 hours. Very good: tender and juicy. As you can see only a bit of the fat has rendered (it floats on top of the juices). 8.5/10
60C/140F for 48 hours. Tender but not as juicy as at 57C/135F. 7.5/10
64C/144F for 24 hours (as recommended by Great British Chefs). Quite dry and only still nice because of the fat. 6/10
68C/155F for 36 hours (as recommended by Serious Eats). Very tender and flaky, but slightly dry. 7.5/10
74C/165F for 24 hours. Tender and juicy. 9/10
77C/170F for 7 hours (as recommended by Anova). Quite firm and slighly dry. 7/10
80C/176F for 7 hours (as recommended by ChefSteps). Quite firm and slightly dry. 7/10
Although I would have to try more combinations of time and temperature to be absolutely certain about the ‘ultimate’ combination of time and temperature for pork belly sous vide, it is clear that a longer cooking time provides a better result. Just like I showed in this post, the dryness caused by a higher temperature can be offset by the additional tenderness from a longer cooking time. I expect that at 70C/158F, 77C/170F or 80C/176F better results would have been achieved with a longer cooking time. It also seems that temperatures between 60C/140F and 70C/158F are suboptimal; as my best results were 48 hours at 57C/135F and 24 hours at 74C/165F. Which of those you prefer is a matter of preference: at 57C/135F less fat will have rendered (which you can consider an advantage or a disadvantage) and the meat is not as flaky than at 74C/165F.