How to remove the excessive saltiness from gammon

A simple way to get "more" out of your salt, is to start with BIG crystals, and coat them gently in oil before sprinkling them over the food. That way they do not melt on contact with the food as they are protected from the water by the film of oil , and add a awesome crunchy texture to the serving.

Technically I think that your question is more chemistry related and not directly cooking related.

I can give you a few hints no what you can do to get crystals, but a chemist should be able to give you a lot better advice.

First, making the salt water solution:

1. Get distilled or at least demineralized water. You do not want to add random minerals that are dissolved in water to your salt :)
2. Make a saturated solution of salt-water at a high temperature ... something like 90-95C (~194-203F). The idea is that at higher temperatures you get more of the salt dissolved in the water more easily.
3. Keep the salt solution at that high temperature (well covered to reduce evaporation) for some time to make sure that any undissolved salt has settled to the bottom. You are interested only in the salt in the solution.
4. Take only the saltwater without any undissolved salt. Until and including this step, the solution should be best keep at the same temperature. If you have to move the solution, at least make sure that the thing that you are moving it into is not cold.

OK, now it is time to make the crystals:

1. Crystals grow. If they grow too fast or are disturbed (thermally or mechanically) they fall apart and end up being smaller. This is why when you make ice cream you churn the ice constantly (mechanical disturbing the formation of possibly ice crystals) or chill it with liquid nitrogen (thermally shocking the crystals and make them break apart). What you get are very small crystals if you disturb them.
2. Crystals grow when they are "forced out of solution" - that is, when the concentration of the salt in water is higher than the solubility of salt in water at that specific conditions. Pressure is one of the factors, but we will just ignore it completely. The factors that you can work with are Temperature and concentration (just remove water from the solution by evaporation)
3. To get BIG crystals, you have to let them grow slowly.
4. So, what you need to do is to cool the solution very slowly AND/OR
5. Evaporate the water out of solution very slowly (take care not to get dust in the solution during this procedure :) )

Unfortunately this is all the advice that I can give you now. Be aware that crystals are delicate and you might need a few attempts until you get the desired result. As a fun fact, there exist conditions where you will actually get a BIG salt Cube aka, a single salt Crystal by doing this :) . Cool indeed , but not very useful for cooking :)

I suspect that the biggest problem here is that your brine isn't anywhere close to being strong enough. Cooks Illustrated has a good guide to the entire process but in a nutshell:

• Sea salt is expensive and inefficient for brining; the impurities actually make it more difficult to dissolve and disperse properly. Kosher salt is generally recommended, although table salt is also fine.

• A typical brine is 1/4 cup table salt and 1/2 cup sugar per quart, which translates to about 70 g and 140 g respectively per L. For very high-heat methods (grilling/broiling), you halve the amounts. Also, for kosher salt you need to double the volume (no change if measuring by weight). Even the lower, high-heat cooking concentration is almost twice as concentrated as what you're doing.

• You also need to scale the amount of brine with the weight of the bird itself. The rule of thumb is 1 quart or L per pound (2.2 kg) of meat. For a whole chicken, which is generally around 6 or 7 pounds, 1.5 L of brine is nowhere near enough, especially if you're brining in a pot as opposed to a bag (does your 1.5 L even cover the chicken?).

• It doesn't really matter if you butcher the chicken first (although most people don't). You're exposing slightly more surface area that way but not really enough to matter.

• Make sure you are actually dissolving all the crystals! From what you're describing, you're getting high concentrations of salt in some areas and none in others. That means you didn't get proper dispersion. You really need to make sure that all of the salt (and sugar, if you're using any) is completely dissolved, otherwise you don't have a "brine", you have water with a bunch of little piles of salt. Some people will suggest heating or even boiling your brine to ensure proper dissolution; just make sure you let it cool off afterward if you do this, before submerging the bird.

In answer to your specific questions:

1. The container should be well-sealed to prevent evaporation, not to mention off-odours in your fridge. However, I've used pots with loose-fitting lids and had no problems. It doesn't make a huge difference as far as the efficacy of the brine.

2. Fridge temperature is ideal. Do not even think about using room-temperature water, that is highly unsafe for storing raw meat for 6-8 hours at a time.

3. As long as you don't overcrowd the vessel and do disperse the crystals properly, the actual amount of space is not a major issue. If it's exposed, it's exposed.

4. Longer than 12 hours is not recommended. Actually, according to CI, longer than 8 hours is not recommended. Don't overdo it - you're brining, not marinating.

5. No matter how you cook any piece of meat, it will give up a certain amount of water and therefore a certain amount of salt (from the brine). Left unstated is why you would even consider boiling a brined chicken; brining is primarily a technique for dry-heat cooking (roasting/grilling), and if you want to boil/poach/braise/whatever then you should be focusing more on flavouring the cooking liquid than the meat itself. I wouldn't bother brining if you're making chicken soup, there are better ways to flavour that.