Effect of starch on crispy potatoes

[somanytoes]

I read in modernist cuisine that starch helps make thing crispy. Makes sense since many fried food are first coated in flour before frying. So I would like to understand why when making fries, potatoes are rinsed first before cooking to remove starch. Heston Blumenthal fries have you first boil the spuds till breaking apart then drained(not rinsed). The purpose is to allow the starch in the spuds to be released and coat the potato so that when the get fried, it will be crispy. Also read somewhere in ATK that on boiling spuds in water with baking soda(softens cell wall) to allow the starch within the potato to be released before frying.

So why soak and rinse potato to remove the starch?

Thanks

[FeChef]

Your supposed to remove as much starch as possible to prevent over browning. The starch turns to sugar, which in turn causes fries to turn dark brown instead of that golden light brown color fries should be.

[somanytoes]

So say I don't care for colour, by not rinsing, will I get a crispier crust?

[FeChef]

So say I don't care for colour, by not rinsing, will I get a crispier crust?

If you want a crispy crust, soak fresh cut fries in ice water for 15-30 minutes. Pat dry with paper towels. Deep fry for 5 minutes. Let them rest in basket for 5-10 minutes. Deep fry again for 4-6 minutes until golden brown. You will get a really nice color and very crispy crust.

[somanytoes]

So say I don't care for colour, by not rinsing, will I get a crispier crust?

If you want a crispy crust, soak fresh cut fries in ice water for 15-30 minutes. Pat dry with paper towels. Deep fry for 5 minutes. Let them rest in basket for 5-10 minutes. Deep fry again for 4-6 minutes until golden brown. You will get a really nice color and very crispy crust.

Why soak the fries in the first step...? Don't potato starch make things crisp.?

Edited January 9, 2013 by somanytoes (log)

[FeChef]

Why soak the fries in the first step...? Don't potato starch make things crisp.?

The starches inside the potatoes dont help crisp. They convert to sugar and promote browning. If you leave the starch in them, they will turn very dark brown before they crisp up. To get them crispy you have to leach out as much starch as you can, and double fry them. You wont find a crispier homemade all natural fry any other way. You could try par boiling them and then dredging in corn starch but i find that to be an off flavor and not natural.

[somanytoes]

Why soak the fries in the first step...? Don't potato starch make things crisp.?

The starches inside the potatoes dont help crisp. They convert to sugar and promote browning. If you leave the starch in them, they will turn very dark brown before they crisp up. To get them crispy you have to leach out as much starch as you can, and double fry them. You wont find a crispier homemade all natural fry any other way. You could try par boiling them and then dredging in corn starch but i find that to be an off flavor and not natural.

What would cause the starch to turn to sugar?, if dredging in starch before frying makes it crispy, why not just not rinse in the initial step so starch remains on the potato surface?. You could parboil or steam then air dry to allow the natural potato starch to leach out right?

[eternal]

FeChef - I think you're really missing the point of the op's questions. He or she isn't trying to find a good way to make crispy fries. I'm guessing he/she already knows how to do that. The double or triple fry methods are widely talked about and understood. The op is just trying to understand why in most cases you want starch for crispiness but in the fries case, you don't.

[somanytoes]

FeChef - I think you're really missing the point of the op's questions. He or she isn't trying to find a good way to make crispy fries. I'm guessing he/she already knows how to do that. The double or triple fry methods are widely talked about and understood. The op is just trying to understand why in most cases you want starch for crispiness but in the fries case, you don't.

Yep, that's it. By not rinsing to remove surface starch, will I affect crispiness? If say I do not give any consideration to colour of fries

Edited January 11, 2013 by somanytoes (log)

[hongda]

Not sure about the validity, but this site tries to explain it

http://www.sciencebuddies.org/science-fair-projects/project_ideas/FoodSci_p042.shtml#background

[M0ng00se]

From my experience its less about the starch and more about the water content of what you're frying. Starchy potatoes are preferred because their waxy cousins have a much high moisture content and don't naturally want to crisp up the way starchy potatoes do. Regarding rinsing, I prefer when I prep potatoes, to let them sit in a salt-water solution, ensure they're really dry and then double-fry in duck fat. I'm not sure that rinsing or not rinsing after cutting makes a huge difference but the type of potato and how dry they are will.

Try it, and let us know if you think theres a discernable difference.

[gfweb]

My understanding is that pectin is responsible for crispness, not starch. A little vinegar in the water (which preserves pectin) if you preboil the potatoes will stiffen them up.

[Zmaster]

Here is a link to cooking issues which they did various tests to get a nice crispy fry. It is a couple of years old and one the french fry recipes published in MC is Dave Arnolds.

http://www.cookingissues.com/2010/04/27/the-quest-for-french-fry-supremacy-part-1/

http://www.cookingissues.com/2010/05/12/the-quest-for-french-fry-supremacy-2-blanching-armageddon/