Ask Peter: Ridding pork belly of impurities
I love slow-braised pork belly cooked in a Chinese-style stock. Before adding the pork to the stock, some recipes say to rid it of impurities, it should be immersed in cold water which is then brought to the boil before being drained off and discarded. Some recommend doing this twice before the meat is browned and added to the stock for slow cooking. Some recipes don’t do it at all. Is this just a way of reducing the grey scum that would otherwise collect on top of the braising stock?
The technique of bringing meat to the boil in cold water is something I’ve done for many years when making stock from bones (meat or fish) and also when braising meat for a stew or casserole if I haven’t diced it myself and it’s become a bit moist.
I even do it to sausages — which must sound slightly bonkers but I find it gives them a much better texture than just throwing them straight on the barbecue or cooking a “toad in the hole” from raw.
In my mind, what this does to meat, in particular to your pork belly, it removes any of the surface blood and some excess fat. By placing it in cold water and slowly bringing to the boil, all the “juices” on the outer surface as well as a few millimetres into the meat, get drawn out of the flesh. Any loose butcher’s paper, loose-ends of string, dust or dirt that have become stuck to the meat, will float up and be easy to remove.
Perhaps it’s easier to picture this in relation to stock bones. In the case of meat bones, say a chicken carcass that’s been chopped through the backbone and leg joints, there is a lot of (solidified) blood, shards of bone, maybe some feathers and guts — bits of liver or heart from the cavity of the bird.
If these are allowed to be in the stock itself, they won’t ruin the stock, but they’ll make it a little more cloudy and in the case of the offal, slightly bitter. In the case of bone fragments and feathers they’ll be strained out once the stock is finished. But excess fat from the cavity, bits of offal and the likes will add flavour to your stock that you may not want.
Fish stock really does benefit from having the bones brought to the boil and rinsed once before making the stock unless you have literally filleted the fish and rinsed the bones under cold running water immediately prior to making it. Even the flesh on one-day old bones can have a less than appealing aroma which will transfer into your stock. You honestly won’t lose much flavour from doing this and the finished stock will be clearer in flavour and texture and possibly much better in aroma.
Meat often gives off a grey (or other coloured) scum when it’s being cooked in a moist environment like a stew or casserole. If you have the time, it’s good to remove it before you start the real cooking, adding onions, carrots, herbs, spices and seasoning.
The benefit of removing the scum before you add your flavours, as it comes to the boil, is that when you’re skimming it you’re not removing the flavour of the dish itself, just the scum. Of course you don’t have to do this at all and it might well be that you can save some time by avoiding it, but I’d suggest you try next time.
The quality of pork in New Zealand varies a little but I’d imagine most of Bite’s readers will be now only be using 100% New Zealand Pork that is pig care accredited.
This meat will produce very little scum, compared to low-grade and badly farmed pork. Other pork products that will give off a decent amount of scum are ham hocks, smoked knuckles and the like as they have been processed much more than a simple pork belly.
The “bring to the boil” technique is key here, so all the chemicals that have been used in the production of these joints (and they’re not necessarily all bad) are drawn out of the flesh and then discarded down the sink rather than being cooked back into your dinner.
For smoked hocks I’ll often bring them to the boil twice, before adding diced vegetables and herbs. This way you needn’t skim the stock too often and you can get on with other chores.
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