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Sous vide is an excellent way of preparing foods by using a plastic bag for cooking, primarily meat dishes. Sous vide is a French word for cooking under a vacuum.
The vacuum is created by vacuum sealing a Ziploc bag.
This method of cooking foods is done by placing the food in a bag and then placing it in a pot with water. The water is not brought to a boil but is heated to the exact temperature of the food’s best cooking temperature.
Ideally, the water should not get hotter than the perfect food internal temperature, and it should not boil.
If it’s coming to a boil, you add cold water to keep it at the right temperature. You keep track of the temperature by having a thermometer in the water.
This method of cooking takes a long time because the water bath slow-cooks the food. This immersion method is popularly used to simmer food to make it tender.
The advantage of sous vide is that the meat is often perfectly cooked because there is little risk in overcooking it. After all, the cooking time is over a couple of hours.
The secret of great sous vide meals is not just in the temperature but in creating the vacuum in the bag where the food is placed. This is because the vacuum makes the perfect condition for the food to be cooked.
Cooking Safely With Plastic
You can safely cook with bags made of plastic if you use the ones that are safe for heat use. The dangerous plastic is made of polycarbonate because when it is heated, it releases a hazardous chemical known as Bisphenol A (BPA).
Kitchen plastic items made of polycarbonate include take-out containers, plastic plates, cling wrap, gallon water bottles, and plastic squeeze bottles.
The safe kind of plastic is made from high density and low-density polyethene, and polypropylene. These are safer because they do not release BPA. However, they are not entirely safe as they release some chemicals when heated.
These bags are BPA free, but they have other chemicals that are thought to interfere with hormone levels in the body.
Safe Plastic Bags for Sous Vide
The safest option for use in sous vide is Ziploc bags which are made with BPA safe kind of plastic. Some purists still feel that non-BPA chemicals are released from whatever kind of bags you use as long as they are plastic.
However, there are vacuum sealing bags that are designed to safely sous vide.
These are known as food-grade vacuum sealing bags made from polyethylene and are BPA free when used for cooking. Vacuum sealing ensures that the bag does not pop open when the temperatures rise when cooking the food.
These bags should be sealed using a vacuum sealing machine to work efficiently as they are designed for sous vide food preparation.
You may also opt to use Ziploc bags that are used for refrigeration or freezing food items. They are thick and can be sealed and resealed with every use.
These kinds of Ziploc bags are made from polyethylene which is a low-density plastic.
When using the Ziploc bags, experts recommend using at least two bags to keep the food from being submerged in the water.
When temperatures rise, the heat will cause an expansion in the Ziploc bag leading it to pop open, and water or air may get in.
You should never use cling film to wrap your food, then place it in a Ziploc or food-grade vacuum sealing bag. When the cling film is warmed in the Ziploc bag or food-grade vacuum sealing bags, it will still release BPA chemicals and contaminate the food.
Just put the food directly in the safe bags, then cook it.
How to Seal the Bag
The best kind of seal for sous vide is using a vacuum sealing system. The sealing machine is fast and very effective. However, it is also very expensive, and not many people will afford to have one at home.
The Process of Sealing Ziploc Bags for Sous Vide
If you do not have a vacuum sealer, you can use the water displacement method or slow immersion method. These methods create a vacuum to cook the food perfectly.
The first step is to place your food in a Ziploc bag. Place the piece of meat at the bottom of the bag. Lay the bag down and begin to push out as much air as you can from inside the bag.
Once you think you have dispelled most of the air, close the zipper-like seal of the bag. However, please do not close it entirely but leave a small space to not completely closed.
The hole should ideally be about half an inch and not larger.
Fill a pot of water. This should not be the pot that you will use to cook. The water should be cool or at least room temperature. Ordinary tap water is sufficient.
The pot of water should be large enough such that the Ziploc bag with the food can fully submerge in it.
The water level in the pot should reach the seal of the Ziploc bag. Slowly submerge the bag with the meat in the container with water. The aim is to have the pressure in the water in the container push air out of the bag.
If you want to know this is working, the bag will begin to wrap itself around the meat, like it is sticking onto it.
When you submerge the bag enough so that the water is almost at the seal, close the remaining part of the seal and seal the bag.
You can then put your well-sealed Ziploc bag in the sous vide machine and cook your food.
The Importance of Vacuum Sealed Bags for Sous Vide
To home cook your meat perfectly using sous vide, the secret lies in placing your meat in vacuum sealed bags. The vacuum is created when there is no air at all in the bag.
Vacuum sealing the bag ensures that your meat is not boiled because if any water is in the bag, it will eventually be heated, leading to the food tasting boiled, which is not the result you intend to achieve.
Sous vide cooking involves keeping the water at a certain temperature to ensure the perfect cooking of the meat. The water is regulated so that meat will not be heated to very high temperatures.
High temperatures lead to denaturing of the proteins in the meat. This happens when grilling or frying meat, which makes the beef sometimes tough to eat or overcooked in some cases.
When cooking using the sous vide method, the water does not transfer excess heat to the meat.
Air heats faster than water, and if there is any air left in the Ziploc bags when cooking using sous vide, this air will heat quickly and reach the equivalent of the boiling temperature in the water and cook a portion of the meat.
This will result in tough, chewy, or stringy beef in those portions instead of the tender meal you expect.
Tips for Successful Sous Vide Cooking
Once you have mastered the art of vacuum sealing your Ziploc bags, some tips will ensure that you have a perfect meal.
When cooking denser meats, meat with bones, and large pieces of meat, ensure that you do not overload the bag with too many pieces of meat or use a heavy-duty Ziploc bag.
This is to avoid air seeping in when cooking because of the temperatures rising, and the bag pops open because of the overloaded bag.
Use multiple bags to ensure that they do not open, and if you do not have heavy-duty sous vide bags, then use two Ziploc bags to ensure that the vacuum sealing is not compromised.
For best results with sous vide cooking, use thick, high-quality vacuum sealed bags with a strong seam closure instead of lighter bags. Thicker bags will hold up well with the cooking and will not open up.
There are sous vide bags available that are designed especially for sous vide cooking. They are designed to withstand high temperatures and the slow cooking time without being affected by the heat.
These are an excellent option for foods that may require higher temperatures, such as lentils, vegetables, and beans. They have a strong closing seam, and with these, you will not have to use two of them; one is sufficient.
You can place a butter knife or a spoon in the bag with the food to help anchor it when it is cooking. If the meat is floating in the cooking pot, it can lead to uneven cooking.
Once you have a sous vide machine, you do not need to get a vacuum sealer to home cook using sous vide. These sealers are quite pricey.
You can vacuum seal thoroughly by using what you already have in your kitchen. Ensure that you remove all the air from the bag to have the perfect sous vide meal.