All about deglazing

My last post on the basics of pressure cooking was me getting very distracted by everything that happens before you have to deglaze – who knew there was quite so much to say about it? - so now onto deglazing proper. This is a process I have been asked about a lot, not just only why we have to do it, but how to do it, as well as what exactly it is. I should say at this point that my pressure cooker based interactions on social media, ramped up as they have been over the last year since Modern Pressure Cooking came out, have given me many reminders on why I shouldn’t assume any knowledge of culinary terms, deglazing included. The other term, besides deglazing, which seems to frequently trip people up is creaming (I cry for all the flat, dense cakes!), but unless you are making a pressure cooker cake – which we will, eventually, come to - it isn’t relevant to this post. I digress…

So what is deglazing? It is simply the process of lifting or unsticking anything that has welded itself  to the base of your pot – whether it is crusty “brown bits” or a more even coating of patina. As so often is the case, we have adopted French terms for elements of this process, not (as far as I am aware) having a British ones. The brown bits are the “sucs” and strictly speaking, the “fond” is the sauce made from these sucs, but they are usually used interchangeably. The lifted sucs are not removed from the pressure cooker and as discussed last time, if you prefer frying/searing/sauteeing in a frying pan before transferring to the pressure cooker, it is still worthwhile deglazing and adding the resulting fond to the pressure cooker too – all those sucs will add flavour to your finished dish. I think I’ve used the words sucs and fond enough now in this post.

These brown bits will usually occur when you sear food. There will be more of a patina build up when you fry or saute on a gentler heat – think of the slightly grainy brown that clings to the pan as you slowly caramelise, onions, for example, or if you are frying off the ingredients of a mire poix (usually finely diced onion, celery, carrot, or in certain US states, the holy trinity of onion, celery, green pepper) and are sauteeing rather than sweating.

Patina can also build up when you use certain ingredients, regardless of the cooking technique you are using, because they gravitate towards the base and will want to stick to it whatever you do. Anything starchy is good for this – as soon as starch starts releasing from potatoes, grains, lentils, it will want to sink and weld itself to the base. Flour (obviously also a starch) and ground spices will do the same, and if you then add anything thick like a concentrated tomato puree, it may form a grainy paste which again, will form a thick coating around your ingredients and the base, not to mention that tomatoes can be tricky, especially when concentrated, as they can scorch.

Leaving any of these be without deglazing may cause problems. I find lots of Internet advice around certain ingredients (especially flour) usually involves avoiding altogether or treating them differently from the way you would conventionally. Most advise not to use flour at the start of a recipe (for example, if you have dusted meat with seasoned flour prior to searing, which does help the end texture as well as the crust), but just thicken later after pressure cooking. This often leads to recommendations to use the dreaded “cornflour slurry” (a phrase which has no business anywhere near food), something I am always keen to avoid. But I think avoiding ingredients or even adding them later can be unnecessarily limiting. I would rather make sure that everyone is aware there might be an issue and learn how to avoid – or at worst, deal with -  the issue rather than the ingredients themselves. And it really isn’t so difficult to do so.

So – we deglaze because if there is too much build up/stickage on the base of a pressure cooker, it won’t want to come up to pressure. In the case of a stove top, this might mean it won’t come up to pressure at all, or take longer than usual and burn in the process. In the case of an electric pressure cooker, the same may happen (I have had instances of electric pressure cookers burning without triggering the burn notice) or the burn notice is triggered which shuts everything down. If you are experienced at pressure cooking and have used your particular model/heat source combination for any length of time, you will be very attuned to whether or not your pressure cooker is taking too long to come up to pressure and can react accordingly. If you are not experienced, don’t worry, it will soon become second nature.

How to deglaze? The simplest way is to add a little liquid – usually given in the recipe – and stirring until the base looks clean and you can tell nothing is sticking to it. This is traditionally done most frequently with some kind of alcohol, but doesn’t have to be, water or stock will work just as well. Sometimes it can be a case of adding more ingredients. For example, if I have seared some meat before adding diced vegetables, the vegetables as they start to cook will give out enough liquid to naturally deglaze. This will only happen effectively if you have reduced the temperature – ie., browned some meat on high, then reduced the temperature to just gently sweat some onion for example.

You can see from the photo below the after I have browned the bacon lardons, the onion is doing quite a good job of lifting up the sucs before I added any liquid.

Sometimes you have to add more liquid – this is usually because if you have used flour or any spices which may behave like flour, as soon as you start adding liquid, it will thicken – a bit like when you start adding a liquid to a roux when making béchamel. But your recipe should make allowances for that. You can see from the two photos below that a patina is building up from frying vegetables and spices - and that when I have added the liquid it has come up completely clean. (The green blobs are frozen blocks of spinach, this was a sweet potato, lentil, spinach soup).

Is it always necessary to deglaze? Or in other words, does the base have to be completely clean before you close the lid? I want to say yes, to avoid any doubt or risk. But the truth is, it depends. And again, this is something you will come to get a feel for over time. The general rule of thumb is, the longer you expect your pressure cooker to take to come up to pressure, the more rigorous you need to be with your deglazing. This is because the risk of burning occurs as it comes up to pressure. So if you are cooking something starchy, and your pressure cooker is quite full and/or you are using cold/tepid liquid - both things which will slow down the build up of pressure - deglazing thoroughly is vital. If you are searing wedges of cabbage and splashing in a little water which will create enough steam for your cooker to immediately come up to pressure – no you don’t, and it would interfere with the process of the recipe if you did. And then there is everything in between. But, if in doubt, do.

Next time my intention is to write about liquid levels which will lead me on to reducing and thickening - unless I get side tracked again, of course. But now might be a good time for me to say that if there are any questions you have about any aspect of pressure cooking which I haven’t yet covered or mentioned in passing that I am going to cover, please ask – it might not be something I have considered.

And finally – I just wanted to share a little good news. Modern Pressure Cooking has been shortlisted in the Fortnum and Mason Awards in the category of Best Cookery Book. I am more chuffed than I can say about this!