[French Fries]

I'm looking at a French recipe where it says to thicken the stock with potato starch. I don't have that here, what should I substitute? Flour? Roux? Corn starch?

[ED BUCHANAN]

Since you say sauce I would say corn starch or arrowroot as it will thicken clear. I have seen things made that called for potato starch where -as instant mashed were used instead.

[French Fries]

Thanks - if that helps, they say to thicken it lightly with potato starch, keeping in mind you're going to also reduce it and then thicken some more with heavy cream. Then I'm adding the green peppers and lightly crushing them with the back of a spoon. Green pepper steak sauce.

I'll try just a bit of corn starch!

[Suzanne]

I'm checking Shirley Corriher's Cookwise. She says that to make 1 cup of medium-thickness sauce, use 2 1/4 teaspoons of potato starch; this will be a clear sauce. Other equivalents are:

For an opaque sauce:

• 1 tablespoon + 1 teaspoon cornstarch
• 2 tablespoons flour
• 1 tablespoon + 1/2 teaspoon rice starch

For a clear sauce:

• 2 1/4 teaspoons potato starch
• 1tablespoon + 1 teaspoon arrowroot
• 1 tablespoon + 1 teaspoon tapioca starch (Asian market)
• 1 tablespoon + 1/4 teaspoon quick tapioca pudding (supermarket)

For a thin sauce use 1 tablespoon of flour per cup; for thick, use 3 tablespoons of flour per cup. You'd need to convert the others in the same way: use half as much for a thin sauce, use 1 1/2 times as much for a thick sauce.

Are you okay doing the math to convert for your starch of choice? If not, tell us

• how much potato starch the recipe calls for, and
• which starch you want to use instead.

Then we can help with the conversion.

[French Fries]

Wow great Suzanne! So since in this case I want an opaque sauce I can use flour instead... good to know. I'll start at 1 tbspn per cup (I'm using one cup so the math shouldn't be too hard ;-)). It's probably all I'll need.

[teamfat]

Originally Posted by French Fries

Green pepper steak sauce.

Green peppercorns, I assume, not green bell peppers.

mjb.

[French Fries]

Yup, green peppercorns. My bad.

[ED BUCHANAN]

Hope you are using the cooked green peppercorns in the can and not out of spice cabinet. If you reduce it enough with cream, you may not need any starch.

[French Fries]

Yup, the canned ones, obviously.

It was delicious! Except... well the flour... I forgot to first add a bit of stock to the flour to make a liquid mix... I just threw the flour in the stock and that didn't quite work. Got lumps and finally I just strained it and continued without thickening. Reducing was enough. The sauce was great - almost a bit too reduced, but it's hard to get the timing right as I was making french fries at the same time.

But it was a great "steak frites".

[boar_d_laze]

Now that it's too late, the reason to thicken with flour instead of corn or potato starch is that flour holds up better.

If you do thicken with flour, you're far better off making a roux first, instead of a slurry. In fact, if you don't have time for a roux, you're probably better off with beurre manie than a slurry. If you do use a slurry or, worse -- add straight flour like you did, count on sieving the sauce to remove lumps and give the sauce some gloss. Sieving is one of those things separating the pros from the Joes.

FWIW, there are flours made for thickening which are very clump resistant, Wondra, for instance. Nice to have in the pantry. It's also nice to keep beurre manie in the refrigerator -- just in case.

Flour holds up better than starch. Starch thickens faster, with less trouble, and better texture -- but breaks down. Arrowroot thickens with almost no cooking, will thicken acidic sauces (which break down starches) but don't hold up well at all.

Hope this helps,
BDL

[French Fries]

Excellent - thanks a lot for sharing all that knowledge BDL.

PS: When is the book going to be released?