I have a biology test tomorrow and I still can’t understand the concept behind this and I think it’ll come out on the test. I need help, badly.
In: Biology
Osmosis is the phenomenon where water is “pulled” towards a more concentrated solution (aka a *hyperosmolar* or *hypertonic* solution) through a semi-permeable membrane (like a cell membrane).
When there is a difference in concentrarion/osmolarity in the fluids on both sides of a membrane, water will pull towards the more concentrated solution until it evens out.
Pickling is adding a vegetable to a hypertonic solution. The vegetable is composed of cells filled with water. The pickling solution will then pull water out of the vegetable cells through osmosis.
From a Google search…hope this helps.
The high concentration of salt of the salt water and the low concentration of salt inside the cucumber need to even each other out so through osmosis the salt diffuses through the membrane.
When you mix salty water and not-salty water, the salt gets distributed around so you get a bunch of medium-salty water.
But what if you put a barrier in the way that salt can’t get through?
Turns out you still get medium-salty water. Since the salt can’t get through the barrier from the salty side to the not-salty side, the water flows instead! The water goes through the barrier from the not-salty side to the salty side until both sides are equally salty. You end up with unequal amounts of water on either side of the barrier. That’s osmosis.
[This illustration might help](https://upload.wikimedia.org/wikipedia/commons/6/62/0307_Osmosis.jpg)
The skin of a cucumber is a real-life example of a salt-proof barrier like this. So if you put a cucumber in salty water, you get osmosis. The water from inside the cucumber will flow out through the skin, until the water inside the cucumber and outside the cucumber are equally salty. As the cucumber loses the water inside it, it shrivels up and shrinks, becoming a pickle.
Here’s how I understand it and it works well enough for a home cook:
Brine is a very salty solution. Because the solution is more salty than the brine, water is pulled out of the meat to try and even it out. But then “oh noes, now the balance is off again” so water along with the salty and other spices are pulled into the meat. This keeps happening until the meat and the solution outside the meat are similarly salty.
Brine your turkeys people. Ain’t nobody wanna eat your nasty Thanksgiving massacre.
Osmosis is the diffusion of a substance through a semi-permeable membrane.
Meat cells are permeable; they may be penetrated. Brine is salt water. The salt permeates the meat during the soaking process. The salt passes through the membranes of the meat cells’ walls. That is brining. Same thing for pickling, which often uses vinegars instead of salt water.
Either method does the same thing. The soaking solution permeates the cells of the thing being soaked, via osmosis.
Think of osmosis as the diffusion of water, so it moves from high to low concentrations.
In the brining or pickling solution the concentration of water (water potential) is low. So during this process solutes (like salt) diffuse into the food, while water moves out of the food through osmosis. Both processes working together will eventually equalise the water potential and salt concentration inside the food and out.
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