So I have been reading and hearing a lot about Robuchon (to name one) boiling his potatoes skin on to counteract gluey mashed potatoes. When I make my mash though I think it's way easier to peel them pre boiling and simmer the potato skin in the milk that I'm later gonna use to emulsify the butter and potatoes.
Normally I have to add quite a lot of milk (2 parts potatoes to 1 part butter and almost 1 part milk) before I end up with a mash that isn't gluey. This makes for quite a loose mash though.
Would it be correct to say that boiling the potatoes with the skin on would lower the risk of having a gluey mash with less milk? And if so, then why?
To give some reference to where I found the habit of using the ratios mentioned above I put a link here to a transcript of a Joel Robuchon mashed potatoes recipe. http://greenmarketrecipes.com/vegetables/robuchons_mashed_pototoes.htm
Also I include a link to a youtube video of Tom Aikens, a former chef under Joel Robuchon, who speaks about the question I am posting here. This is the reason for my question in the first place.
https://youtu.be/S-Gkne6skXc?t=25m19s
Best Answer
I've never heard that boiling potatoes skin on makes a difference in consistency, but it's possible. The skin will act a as a barrier to moisture, letting the potatoes cook while absorbing less water. That will only work if you keep the potatoes whole though, cutting them up will negate that somewhat.
While skin in may make a difference the choice of potato makes a bigger difference. Waxy potatoes are not a good choice, neither are dry ones like russets. A medium starch potato is best, like a yukon gold or a maris piper.
Also very important is preparation after cooking. I find using a mixer tends to overwork the potatoes and make things gluey, while most chefs would recommend using a ricer. A ricer does give a great result but it is messy and lots of work. I use a potato masher and do it by hand, which to me is a good balance between speed and cleanup while giving a good result.