There’s an argument in our house, G (my darling wife) insists that the best form of potatoes of all time are roast potatoes. I think mash wins hands down. So every Christmas that we go back to Australia we have two types of potatoes on the table – the Libling family tradition of creamy mashed potatoes with slow cooked onions and peas and G’s favourite, a pile of golden roast potatoes. This year though my side of the potato argument started to get a bit more lonely – my dad deserted me to the roast potatoes camp and I think my mum did too. Only my loyal little brother remained on my side (he’s taller, stronger and broader than I am but he’s still younger and hence will always be little). I like to think they’re only deserting me because after many trials I’ve finally cracked roast potatoes – G even went so far as to say they were the best roast potatoes she’s ever had (considering she ate no fewer than 7 on Christmas day, she’s has her fair share in her time).
For me there are a few non-negotiables when it comes to great roast potatoes:
- They have a crispy and crunchy outside layer that’s almost glassy
- They have a fluffy interior
- They’re an amber colour which indicates the starch has caramelised and developed a “roasted” flavour but they haven’t developed any bitterness
- How you cook them has to be simple and easy to do
- You must have lots of them
In a sense, they’re very similar to chips in those respects and so I took my lesson from Heston Blumenthal’s triple cooked chips. You’ll be pleased to hear though that I’ve simplified the process from Heston’s recipe and you don’t have to do anything like freeze the potatoes or use a chamber vacuum sealer to remove moisture as he recommends, you also only have to cook the potatoes twice – boil them and then roast. I know it all sounds very traditional but there’re a couple of tricks that will really make the difference and mean you never have to have anaemic roast potatoes again.
Firstly let’s understand what makes a potato crispy – the crunch is starch which has caramelised. This happens when the starch dries out under heat. So for extra crispy potatoes, starch is your friend and water is your enemy. This leads us to tip 1:
1. Choose the right potato: Choose a medium or high starch potato which will be labelled good for mashing, chipping or roasting. The higher the starch content, the better they will be except for one crucial fact – high starch potatoes also absorb the most water when boiled (this moisture absorbtion is what makes them great for mashing as they can absorb the fat you add better). The higher the starch content, the more work to get rid of that moisture and get perfect roast potatoes, which leads us to tip 2:
2.Boil (not parboil) your potatoes first but then remove that moisture: Boiling the potatoes means you’ll have perfect fluffy interiors to your roast potatoes every time. You actually want to boil the potatoes until they’re about to fall apart and be as careful with them as you can – you’re not parboiling them! Boiling also helps you get crispiness by opening up the starch vacuoles within the potato which allows for more caramelisation (crispiness) on the surface. However, boiling the potatoes fills them with moisture which leaks out when you roast them and stops your roast potatoes from being the glorious, amber beauties they want to be and instead more resemble Bernie from “A weekend at Bernie’s” – pale, limp and lifeless. To get rid of the moisture leave the potatoes to steam dry in a colander and then ideally transfer them to a fridge (uncovered) for as long as you can (up to a week but overnight is all you need). For me this is another way to get ahead with the cooking like I’m always advocating but if you’re really in a rush then you don’t have to refrigerate them – use a slightly less starchy potato and leave them to steam until cool. Because you’ve boiled them properly and not just parboiled them you should find the edges are really roughed up – this is great because the more surface area them more crispy your roast potatoes will be, in fact that’s tip 3:
3. Maximise the surface area: The more surface area, the more of the potato can dry out and absorb the oil you’re cooking the roast potatoes in and go crispy. The folks over at modernist cuisine use a super fancy sonic water bath normally used to clean jewellery to create lots of roughness on the edges of crisps – frankly that’s a little absurd. So just cut your potatoes in half lengthwise (it honestly makes a difference) to get a really large flat surface. Then when your potatoes have been boiled and drained, toss them (very lightly so they don’t fall apart) in the colander to rough them up a little.
4. Roast them relatively gently for long enough: Many recipes call for really high heat (190 degrees plus), they also sometimes say to heat the oil in the oven first and then add the potatoes to hot oil. They suggest cooking them for 30-40 minutes. In my experience this gives you fairly anaemic roast potatoes without any depth of colour. I find that 170-180 degrees is much better and that you want to take your potatoes cold straight from the fridge and coat them generously in the roasting fat in the tray. Then place them (still cold) straight into your preheated oven and leave them for 60-80 minutes. Don’t touch them for at least 50 minutes, just like browning a piece of meat you want to leave the roast potatoes to do their roast potatoes thing. Lots of people also get really het up about what you roast them in – some say duck or goose fat, some say dripping and some say oil. The truth is so long as it’s something which can stand the heat (e.g., definitely not butter) you’ll get good results. Different fats have different flavours and the flavour of duck or goose fat is lovely and is my favourite (you also get a slightly deeper colour due to a different reaction called the maillard reaction which occurs with animal fats). I actually find olive oil gives some of the best results though so I wouldn’t get too fussed about it, just make sure there’s a really good covering in the tray.
With these simple tricks, you can not only get perfect crispy roast potatoes every time, but you can also cook part of it ahead and then just roast your potatoes at the same time as your meat. I just hope I haven’t added too many people to the roast potatoes over mashed potatoes camp because even these beauties don’t beat mashed potatoes with slow cooked onions and peas!
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- Enough potatoes – they should be medium to high starch potatoes
- Olive oil/Animal fat (goose/duck/beef)
- Peel the potatoes and slice them horizontally to maximise surface area.
- Boil them in salted water until very soft and almost falling apart. This will take 15 minutes plus depending on the size of the potatoes but they should have no real resistance when speared with a fork.
- Drain them in a colander and leave to steam dry and cool. Once cool, toss them lightly in the colander to “roughen them” without breaking them. Transfer them uncovered to the fridge and leave to cool and dry overnight (or as long as you can). They can stay in the fridge for up to a week but if leaving them more than overnight, cover them with cling film.
- Pre-heat the oven to 175 degrees celsius. Pour a 1cm layer of olive oil (or other fat if using) into the roasting tray and toss the potatoes in the oil. Place the potatoes cut side down and roast in the oven for 60-80 minutes or until deeply golden on the cut side. Don’t check them for 50 minutes but then check every ten minutes or so to make sure they don’t burn.
- I prefer my potatoes with one crispy side and one not crispy side so I stop here. If you want a little more roasting on the other side then flip the potatoes over and roast for another 10-20 minutes to lightly crisp the other side. Season with salt and serve the roast potatoes immediately.
TimedEating Tips and Tricks for cooking ahead:
- You can boil the potatoes up to a week in advance and keep in the fridge. I keep them uncovered at first to drive off moisture but if you’re keeping them a full week you will want to cover them so they don’t take on flavours from over things in the fridge.
- I’ve had a couple of people ask me if you can roast the potatoes in advance to save oven space. This has a couple of problems but can be done in a pinch. The first problem is that they get less crispy as they cool. The steam from inside the potato softens the outside and makes it leathery. The second is that when you reheat them they can dry out before they recrisp again making them leathery. However, in restaurants you need to make large batches and then hold them for a while. They can hold for about an hour if you keep them in a warm place in one layer, to reheat give them a blast in a hot oven.
- I wouldn’t recommend freezing them unless you have to. When you freeze the boiled potatoes it can then be very difficult to then get them to crisp up properly. However, if you do freeze them then I would recommend defrosting in the fridge and then allowing an extra ten minutes cooking time
- Leftovers won’t reheat to crisp very well. However, I very rarely have leftovers and if I do, they quickly get used up by being chopped up and then warmed through a Spanish omelette or my personal guilty pleasure – warm roast beef and roast potato leftover sandwiches with srichacha mayo!