Next time you roast a joint of belly pork I would definitely recommend brining it in advance. Brining improves the texture of the meat, keeping it moister, and also seems to help with crackling formation. If you get the brine right you don’t have to worry about seasoning the outside. And you can also add some complementary flavourings which will penetrate within the meat- I chose juniper, bay leaf and garlic, mainly because they were to hand but you can express yourself. I cooked a small belly joint around 1.5kg for around 2.5 hours at 130 degrees C and then cranked up the temperature to around 210 degrees C for 20 minutes to finish the crackling.
My continuing campaign is that all brine recipes are expressed in terms of percentage strength, and include the weight of the thing to be brined. So, if you are aiming for an end-result of 5% salt, and you have a 2kg (2000g) piece of pork and cover it in 3 litres (3000g) of water, then you would calculate (2000g+3000g) * (5/100) = 250g of salt.
Again I am struck by the variability in recipes out there. The venerable Fergus Henderson, suggests in his brine recipe 600g of salt to 4 litres of water and does not specify the weight of pork belly. Assuming a 2kg piece, then this would be a 10% brine. He would have you brine for 3 days. I suspect this will result in something unpalatably salty for most people. This recipe from Anna Hansen uses less salt, but unhelpfully does not state how much water to include just to use enough brine “to cover”, which doesn’t take into account the variability in your pot. As an aside, if whatever I am brining can fit into a Ziploc bag, this is my preferred method. Just be sure to double-bag it in case of any leaks. I can’t even work out the brine strength for this New York Times recipe as they use the insane Imperial system (actually the US customary units system, come on Americans get with the programme – yes, that’s two m’s and a e).
So in conclusion, when brining, consider how salty you would like the result to be, I would suggest a palatable range is between 3 and 5%. I find it neat that sea water is around 3%, a nod to our amphibious past? You can find out what you like through experimentation. However, bear in mind that curing is not particularly efficient and you should consider at least two additional factors: time in the cure, and thickness of the meat. I suspect that explains why some recipes call for such high salt concentrations. There is considerable variability in terms of length of time required to cure and this mainly depends on the thickness of your pork belly. A thin piece should be done in 24 hours, but thicker pieces will require longer.
I am working on a Unified Field Theory of Brining, but still need to figure out some of the formulas involved. Call me Brinestein.
So, a few questions for advanced blog readers:
- What is the formula governing brine uptake into meat at a certain temperature by thickness? I.e. can we predict the salt concentration at 1cm, 2cm, etc. after N days at fridge temperature if we know the starting salinity of our brine?
- Why does brining improve crackling? One could argue that it is due to dehydration from the salt, but this would not make sense as it makes meat moister due to uptake of brine into the lysed cells. Is it due to a physical effect of breaking down the skin structure, e.g. forming cracks, perhaps similar to the technique of pouring boiling water over the skin?
