I cooked some pork chops at 145 for close to 1 hour and 30 minutes. They were around 1 inch thick, so I would’ve though that was plenty of time. I took them out and put the bags in a bowl while I prepared to open them. I opened them maybe three minutes after taking them out of the water, and checked the temperature right after opening. They were only at 143* F. I’ve tested my thermometer in the sous vide water recently, and know it’s within 0.2* F. Did it show 143* because it didn’t get up to 145*, or because it cooled quickly instead of getting warmer like traditionally cooked foods?
I should mention I’m more curious than anything else since I know the Serious Eats site also says you can cook them at 140*.
Interesting. The standard theory is that the temperature takes around 30 mins per half inch to penetrate the meatt (based upon Douglas Baldwin). There would probably be some insulation/temperature retardation caused by bone running through the middle. What cut of pork were they?
2F is a very tiny amount in the grand scheme of things, so I wouldn’t be too worried about the difference in this instance, but it is an interesting finding. Personally, I do pork at 130F, so there is quite a range of acceptable temperatures for most meats.
They were boneless pork chops…not sure of the specific cut. Do you usually give 30 minutes per half inch for the meat to come to temperature, plus additional time for pasteurize for? I’m wondering if I’m reading the recipes wrong. Most of the ones for small cuts seem to say to cook for 1 to 4 hours. Should I start timing when I put the food in the water, or once the food has likely gotten to temperature? The Serious Eats temp and timing guide for pork chops said 1 to 4 hours. I gave them about 1.5 hours figuring that would give me a good buffer. (I’m still a bit nervous about cooking at low temps and have seen charts in science articles that recommend cooking st low temps for longer than what the recipes seem to suggest. I’m a bit confused by that.)
OK. I’m going to get controversial here. Are you ready?? 
Most meats do not require pasteurisation.
There. I’ve said it. And I feel much better for it. Hopefully you will too.
This is why we can eat rare or even raw beef. No matter how long you cook a steak at 52C/126F it’s not going to pasteurise because it’s below the pasteurisation temperature. Now, provided it is kept below the 4 hour mark at this temperature it will be safe to eat.
The same thing with a pork chop. There is no requirement for it to be pasteurised. Pork is now treated a whole lot better than it was decades ago and it’s safe to eat a medium rare temperatures. It’s safe to eat it at rare temperatures too, but it’s not got a very pleasant texture. Lamb is another candidate that is at its best when medium rare. The same with venison, goat, duck, kangaroo and a whole bunch of game meats (provided there is no problem with parasites… You’ll have to talk to the hunters for information on that score.)
When we’re talking of longer cooks like roasts or ribs, beef cheeks or pork belly, things that need cooking for longer than the 4 hours to get satisfactory breakdown of the collagen to provide the tenderness we desire. Then we need to cook over the 54.4C/130F safety temperature because they will be cooked for long periods of time. At 54.4C/130F collagen starts to break down but the process takes considerably longer at this temperature than it would at say 70C/158F.
*Note: pasteurisation is a consideration for chicken. Some people have concerns over raw or near raw eggs. It might also be a requirement for pregnant women… Ummm… I mean when cooking for pregnant women.
I’ve probably made a bit of a hash at explaining this today. I usually do much better. Here’s a slightly better explanation of the way time and temperature affect the outcome: Many steaks at once - #6 by Ember
To understand the sous vide process fully it is well worth reading Douglas Baldwin’s work upon which all of the Food Safety Standards for Sous Vide are based.
A Practical Guide to Sous Vide
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I know the food system is much better than t was, I’m just not willing to risk it. I’ve taken a few too many infectious disease classes. Even though severe food poisoning is rare, it still happens and can have quite severe, life-long consequences. The surface of many meats can be contaminated throughout the food production system and there’s no good way to tell if that’s happened. Some pathogens associated with certain types of meat can also get into the muscle, requiring certain internal temps for those types. I’m well aware of the fact that it doesn’t happen often, but, I’d rather not risk it. I’ll stick to foods in a temperature range I’m more comfortable with, and am really just interested in the proper point to check the temperature.
On your original question about the temperature normally going up. This will not happen with sous vide. There is no heat source for the energy required to raise the temperature. In a roast for example the temperature at the edges of the roast is far above the core temperature when you take it out of the oven. Some of the heat is lost through radiation outward and some is conducted inward raising the internal temperature. With sous vide it has no residual source of energy so it can only cool down once it is removed from the bath.
You really need to read the Baldwin Guide then so that you have a full understanding of sous vide and food safety, particularly if you have concerns about food safety.
I’ll check it out! Thanks!
That makes a lot of sense! Thanks!
I would say it cooled since cooking with sous vide will not keep increasing the temp after you stop like with other methods. You cook at a steady temp and that’s what it will be when you take it out. It can only cool down after that. With other methods, you cook at high temps and it will keep increasing by a few degrees when you take it out, not with sous vide.