Why did my bechamel/cheese sauce fail?

[satguy123]

Hi All
Im trying to figure out why something like this would happen to a sauce. Its never happened before to me.

Made a fairly good cheese sauce recently. The texture was great, nice and thick and cheesey, taste was good and most important of all it was grain free. It was smooth as cheese sauce should be. At least it was at the start.

Basically i took:
50 grams unsalted butter
3 Tablespoons corn starch
900ml of milk
3 cups of grated masdam cheese (nice melting European cheese)
1 Teaspoon of salt

Melted the butter. Took it off the heat and added corn starch and whisked together until lump free.
Put it back on the heat and added the milk and again whisked together continuously just like making a bechamel sauce.
The sauce thickens up nicely after 5-10 min and i turn the heat down and keep cooking it a bit longer to get the raw corn starch flavors out.
Took it off the heat and let it cool down a little so as to not overcook the cheese in the next step.
Then 1 handful at a time i added the cheese while whisking at the same time.
at the end added the salt to taste.

The result was a very thick,smooth and very nice tasting cheese sauce. Then as it began cooling it started taking on a more liquid gelatinous consistency. By the time it had cooled completely over an hour it was as liquid as the milk i started with. The sauce was ruined.

My question is what's the scientific reason behind this? And what steps can i take to stop this from happening.

thanks

 

[Zhizara]

In my experience anything thickened with cornstarch will break when cooked too long, and with cornstarch that's not a very long period of time.

Even when you get it right, it doesn't reheat well or freeze well. I always use flour because of this.

 

[CraigC]

I also think it is because of the corn starch. Never heard of anyone not using flour for a roux.

Craig

 

[garlicjosh]

I also think it is because of the corn starch. Never heard of anyone not using flour for a roux.

Craig

agreed

cornstarch like many thickeners will break at some point. The starch sucks up all it can and if it keeps cooking it just pops and you are back where you started

 

[satguy123]

the reason for the cornstarch was that i needed a smooth consistency. Flour makes the sauce just too grainy for a cheese sauce which needs to be smooth in texture. I have used flour in the past for a cheese sauce and it was a failure due to the grainyness.

I want aware that thickeners break down when overcooked. Thanks for the tip. I will try again using a shorter cooking time.

By the way the idea of using corn starch instead of flour i got from this article:
The Burger Lab: Cheese Sauce for Burgers, Fries, and Chips | A Hamburger Today

 

[jennyema]

In my experience anything thickened with cornstarch will break when cooked too long, and with cornstarch that's not a very long period of time.

Even when you get it right, it doesn't reheat well or freeze well. I always use flour because of this.

Exactly right. Why did you use cornstarch instead of flour?

 

[jennyema]

the reason for the cornstarch was that i needed a smooth consistency. Flour makes the sauce just too grainy for a cheese sauce which needs to be smooth in texture. I have used flour in the past for a cheese sauce and it was a failure due to the grainyness.

I want aware that thickeners break down when overcooked. Thanks for the tip. I will try again using a shorter cooking time.

By the way the idea of using corn starch instead of flour i got from this article:
The Burger Lab: Cheese Sauce for Burgers, Fries, and Chips | A Hamburger Today

Flour doesn't make béchamel sauce grainy if you make it correctly.

 

[Silversage]

the reason for the cornstarch was that i needed a smooth consistency. Flour makes the sauce just too grainy for a cheese sauce which needs to be smooth in texture. I have used flour in the past for a cheese sauce and it was a failure due to the grainyness.

I want aware that thickeners break down when overcooked. Thanks for the tip. I will try again using a shorter cooking time.

By the way the idea of using corn starch instead of flour i got from this article:
The Burger Lab: Cheese Sauce for Burgers, Fries, and Chips | A Hamburger Today

No one is better than Kenji at the food science stuff. But you didn't follow his instructions or his recipe. His sauce calls for for 1 Tlbs of cornstarch, 1 12 ounce can of EVAPORATED milk, and 8 ounces of cheese, at least half of which needs to be a high fat/low moisture cheese such as cheddar.

If you want his results, follow his recipe instead of adding butter, substituting milk for evaporated milk, and using a higher moisture melting cheese. I'm quite sure that if you followed his recipe, you would have had better results.

For those who don't recognize Kenji, for years he was with America's Test Kitchen. He created and tested many of their recipes, and if you subscribe to Cooks Illustrated, you'll see that he wrote many of the articles. He recently left and moved to New York (I think it had to do with getting married), and is doing a food blog called The Science Lab for Serious Eats. His stuff is really good and detailed, just like ATK.

 

[satguy123]

Flour doesn't make béchamel sauce grainy if you make it correctly.

No matter how well they are made, there is still a faint graininess to them and a distinct flavor that may be appropriate in a lasagna or a Hot Brown Sandwich, but not for fry-cheese.

 

[Josie1945]

Welcome to DC.

Josie

 

[Bolas De Fraile]

Mate I could fill a bath with the amount of bechamel I have made using flour without it ever being grainy, if you do not cook the Roux "out" enough it my taste raw. A classic UK dish is cauliflower cheese if you use corn flour in the sauce it will break down when you bake it, this also applies to meat pie fillings.

 

[Zhizara]

If you are concerned about graininess, I suggest you use a finer flour.

 

[Nicholas Mosher]

I would suggest learning to make a proper béchamel through experimentation. You need to cook a béchamel long enough for it to lose it's "grainy" texture. With a light roux, you also need this extended cooking time to remove the "raw" flavor of flour that sometimes persists in light sauces (I give mine at least an hour). Once this point has been reached, you can then add your cheese(s) for the Mornay. Weeping is a classic problem that occurs with cornstarch thickened sauces.
-----
On another note, I would disagree with the "Absolute" comment regarding the peerless quality of the America's Test Kitchen employee. While I find ATK an entertaining show/magazine, they're sometimes horribly off base with their science and history.

 

[Silversage]

On another note, I would disagree with the "Absolute" comment regarding the peerless quality of the America's Test Kitchen employee. While I find ATK an entertaining show/magazine, they're sometimes horribly off base with their science and history.

You're putting words in my mouth. Neither I nor anyone else said "absolute" anything. I just told him that if he was trying to make Kenji's sauce (which by the way, was not called a bechamel in the linked article - he was trying to duplicate the cheese sauce from Fuddruckers Restaurant), he should follow the directions. Don't follow half of someone's directions, then then go somewhere else and ask what went wrong.

It's kind of like saying "I made your spaghetti recipe, but I didn't have pasta so I used rice, and I didn't have oregano so i used tarragon, and I didn't have garlic so I used......"

 

[garlicjosh]

I do strongly agree in the not subbing of things in such recipes.
However, I have used flour a great deal in my own and in many of my other sauces and have NEVER had a grainy section or a cereal taste that is oh so common when people don't cook the roux long enough.

I would go back and try the recipe one more time with the evaporated milk, I must have missed that in the post some how, that will make a great deal of difference. I would have a hard time dismissing one of his recipes myself.

 

[Nicholas Mosher]

No one is better than Kenji at the food science stuff.

That is an absolute claim.

The original poster was not following the linked recipe, he simply used the idea of thickening the sauce with cornstarch due to difficulties with using flour. Contrary to your position, anyone can try to be creative and then politely ask what possible explanations exist for a certain result.

From his post, I gather he is trying to make a smooth cheese sauce, which is why so many others chimed in about a Béchamel (including myself).

 

[garlicjosh]

makes sense to me Nicholas

 

[Rocklobster]

No matter how well they are made, there is still a faint graininess to them and a distinct flavor that may be appropriate in a lasagna or a Hot Brown Sandwich, but not for fry-cheese.

Hey, welcome. I disagree with this post, satguy.

 

[Silversage]

Hey, welcome. I disagree with this post, satguy.

That post is exactly my point. I suggest we all read the link before criticizing. The original poster quoted the following verbatim (although without giving credit) from the blog article, describing what he was trying to achieve. He is looking for a cheese sauce for his fries, not a bechamel. This sauce is to stay smooth, silky and flowing even when cooled.

No matter how well they are made, there is still a faint graininess to them and a distinct flavor that may be appropriate in a lasagna or a Hot Brown Sandwich, but not for fry-cheese.

In the article, the author clearly differentiates a cornstarch based sauce from a bechamel. I suspect our OP has never actually experienced graininess in a flour based sauce, but read the article, and so adopted the thought. If he was actually trying to achieve a bechamel, the advice given by many posters was definitely correct. But all too often online, we all want to answer the question that fits our knowledge, rather than the question that the poster needs answered. And too many people read the first question and never take the time to read the rest of the information that follows.

Perhaps we're all at fault for not first asking him what he intended to do with his sauce, before we offered up answers.

Further, Nicholas, I'm at a loss as to why you feel so threatened by a comment giving Kenji Alt credit for being very good at food science and experimentation. He's very highly regarded for his work. Yet you seem positively angry about it. Would you feel the same way if I said something nice about Alton Brown, Harold McGee, or Michael Ruhlman? Or is it just his past affiliation with ATK that you object to?

 

[Rocklobster]

Just microwave some Cheeze whiz. Close enough.