Tenderness of sous-vide pork chops

The actual minimum temperature which kills the roundworm Trichinella spiralis is 137F.

Therefore it is recommended that you sous-vide pork at a temperature of 138F or higher. If you do not have a high quality immersion circulator with precise temperature control and your water bath temperature can vary by a few degrees, it is recommended to use at least 140F.

I use an industrial polyscience immersion circulator and I have found that cooking pork at 141F yields extremely tender meat that is both medium rare and safe. I had whole marinated pork tenderloins that I cooked for 6 hours this way and they came out tender enough to cut with a fork.

I also put a quick sear on the pork with a hot cast iron pan immediately after taking it out of the bath for additional flavor from the Maillard reaction.

FWIW, marinating meat in a salty sauce (fish sauce / soy sauce) will draw water out of the muscle fibers and make the meat tougher -- this is especially true for thin cuts like your 1cm thick chops.

Try marinating in the spices and seasonings with a bit of oil minus the salt or salty sauces (at the very least, reduce the amount of salt in the marinade). If you have a chamber vacuum, you can marinate in the sous vide packaging under vacuum which will lead to more intense flavor using a lot less marinade. After sous vide cooking, apply a small amount of your salt or salty sauces when serving the pork.

I think your mistake was to marinate them overnight in soy sauce. As it is salty it can start to preserve the meat and make it a bit like jerky.

I've had beef pieces that were almost petrified from about 2 days in a soy and ginger marinade.

I've had some similar results with pork chops. I think part of the issue was the quality of the meat I was using. A nicer cut of pork from a local farm was much better than something from the Kroger (grocery store).

You may want to cut your marinade time down. You essentially did 16 hours, as you cooked in it too. I generally just brine for 1-2 hours in a 7% salt 3% sugar brine, and then take that off before cooking.

How did you determine your cooking time? The amount of time you cook Sous Vide for can alter the texture in some rather unpleasant ways (Lobster particularly). Depending on the cut of your meat, you may have been able to take it out much earlier. If you're not using it regularly already, I strongly recommend Douglas Baldwins: A Practical Guide to Sous Vide. I haven't read his book, but the online resource is invaluable.

Based on Baldwin's charts, you would only need to cook a 1cm pork chop for 1:21 minutes to reach a safe zone. So you cooked it for 6 times longer than necessary. If I recall correctly, it's not recommended to leave lean meats cooking for more than 2-4 hours longer than necessary, and you definitely exceeded that.

The advantage of sous vide is fine temperature control. There are two basic ways to use this control. The first is to hit a desired temperature exactly and consistently through a piece of meat. This is ideal for tender meat with low fat content. In these cases, you should cook the meat for the minimum safe time give or take some for convenience as extended cooking will affect the texture of your dish. The second way to use it is for low and slow style cooking that allows you to have all the benefits of long cooking time and tenderizing nature but without having to cook the meat to well done. The second method is perfect for short ribs, roasts, a boston butt. However, if cooking something like pork chops, the extra cooking time won't make the end result any more tender and will eventually have an adverse effect.

I had similar experiences, and I've found that there is a big difference for long cooking between 132°F and 138°F (55°C vs 57.5°). Try a slightly higher temperature next time, you should be pleasantly surprised!

A few things I can suggest

1. To tenderise pork chops is to use onion in your marinate. Onion is a very good tenderiser, which won't affect your recipe a lot. You can have chopped onion in your over-night marinate and leave the onion out in your cooking.

2. Another trick that I was taught by some Chinese chefs is to let Pork chops to absorb water when you marinate the pork chops. When you prepare your pork chops, you can lightly bash them. After that you can add a bit of water (about 1/4 cups per 4 chops) in a bowl with the bashed pork chops, then you will see the pork chops magically absorb the water and then you can marine the pork chops. (Please note that if your marine has a lot of liquid, maybe you can consider skipping the pork chops absorbing water. However, bashing the porks would be essential.)

3. Avoid putting salt in your marinate. Salt can make red meat hard. However, you can apply salt in your cooking process.

I agree with Grace.

I find that very lean cuts of meat (rack of lamb and pork tenderloin, eg) do not do as well in the sous vide over longer periods of time. 2-4 hours at 135 degrees seems to work for me.

I also find that over-salting and/or marinading can sometimes change the texture of some meats (maybe brining is the answer like Grace says). In my earlier experiments, I tried to add as much flavor as possible and cook for as long a time as I could in the sous vide (more=better, right??). I once salted a leg of lamb and cooked for 48 hours -- the taste and texture are difficult to describe, but the best I can do is "lamb baby food." Truly awful...

Very tough meats with lots of connective tissue (short ribs!) do very well for longer time periods. I think it has to do with breaking down the proteins in the connective tissues -- the longer cooking time "melts" the connective tissue out of the meat. You have not lived until you have had 48- or 72-hour sous-vide beef short ribs.

I also find that I like to season with salt (or anything with salt) after the fact. This is a personal preference -- I have seen many arguments online for and against. It just seems to work for me.

Try 140F for 1 hour. 8 hours is too long for a relatively tender cut like pork chops. Give it a quick 20 seconds post sear afterwards to finish.

Try brining instead of marinade that contains such a high concentration of salt. That partly contributed to the dry/tougher texture too.

Was the real problem tenderness or dryness? Meat continues to lose moisture as it cooks, so there's a fairly complex curve relating tenderness to time and to juiciness. A very long-cooked piece of meat will be more tender than a short-cooked one, all else being equal ... this is because of thermal breakdown of collagen, and in some cases to enzymatic breakdown of other proteins. But it will be less juicy. You'll be able to measure more juices lost to the bag, so this isn't surprising.

There's no compelling reason to cook any part of the pork loin for several hours. I'm a bit surprised that it wasn't tender, but not at all surprised if it tasted dry, and if the doneness wasn't what you wanted. Most people like this cut on the pink side of medium, usually around 60C / 140F or a few degrees under.

You do NOT have to worry about trichinosis. It's a practically non-existant parasite in the developed world and it's easy to kill. The USDA guidelines are ludicrous. Trichinella worms are killed at 130°F in 112 minutes, and at 140°F in 12 minutes. I can promise you will die of something unrelated.

The time advice you're getting doesn't take the thickness of the chops into account. A doubling of thickness will result in about a 3-fold increase in cooking time. Here are some very general guidelines, if you're going from fridge temperature to 60C / 140F are 1” thick: 40 minutes. 1.5” thick: 1 hour 45 minutes. 2” thick: 2 hours 20 minutes.

Small changes in temperature do not make much difference; small changes in thickness make a substantial difference. Thermodynamics, etc..