Questions about the chemical composition or properties of ingredients and dishes.

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6
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3answers
9k views

what makes red tomato sauce turn orange in colour?

I have noticed that tomato sauce (having started with deep red tomatoes) can turn orange. The colour change isn't from mixing in an ingredient of different colour such as cream. It seems to occur in ...
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2answers
2k views

How can I clean these brown iron stains in my pot?

I use a big aluminium pot to boil water. I think the water contains iron because after 4-6 months, the inside of the pot is full of brown stains. The colour is just like ferric. There are lots of ...
10
votes
1answer
3k views

What determines the 'saltiness' of salt?

I've bought two brands of salt that are completely different in terms of 'salt' concentration(not sure if this is the correct terminology). I realized this because I needed three or four times more ...
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votes
4answers
7k views

Why does salt prevent soy milk from curdling in hot coffee?

As many people have experienced, soy milk will often curdle in hot coffee. I've experienced this myself with both instant and fresh coffee, and with my homemade soy milk (not my favorite soy milk ...
8
votes
2answers
1k views

What factors affect collagen to gelatin conversion?

I have a bunch of oxtails I've been braising for hours in an adobo sauce and they remain awfully tough. What I'd love to see happen is for that abundant connective tissue to melt away and coat each ...
2
votes
2answers
5k views

PH and sour / acid taste

I had always thought low pH foods had a noticeable sour (acid) taste, and vice-versa. But when reading The Bread Builders by Daniel Wing & Allan Scott, on page 54, it says: The sour taste of ...
3
votes
2answers
3k views

Differences between gel and gelatine

Are they physically different? If so, what is the difference, between a gel and gelatine, or it's proccesses gelation and gelling (gelatinization. gelatinisation)?
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vote
1answer
612 views

Why does chewing gum sometimes change its texture

Although this is more a general food related question, I wonder why chewing gum sometimes changes its texture and looses its chewy quality?
3
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1answer
964 views

How come mere water buffalo milk and lemon juice mixture turn into yogurt?

Yogurt is produced by the fermentation of lactose in milk by the bacteria of yogurt-ferment. Without those bacteria it is not possible to make yogurt. But surprisingly, water buffalo milk and lemon ...
4
votes
2answers
823 views

By what reactions do moisture and light steal away my coffee's freshness?

Typically, the standard advice for prolonging your coffee is to store it in an air-tight, light-tight, dry container. At a chemical level, what happens when coffee is left in humid or sunny conditions ...
2
votes
1answer
2k views

Why should I add salt to my curries?

I've been advised by a friend of mine that I have to add salt to my curries if I want the spices to come out and not leave me with a bland curry. Now after being a doubter, as I never add salt to my ...
2
votes
1answer
197 views

Separating Chlorophyll didn't work

I tried to extract chlorophyll from spinach by blending up some spinach and water and straining out the green juice, then heating the juice. I've done it before, but this time, it wouldn't separate. ...
8
votes
1answer
4k views

What turned my garlic purple?

I commonly use a technique when caramelizing onions, in which I add the sliced onions to a pan with salt, oil, and water. The water softens the onions and helps cook them evenly such that by the time ...
11
votes
2answers
4k views

Why do people recommend cream of tartar when whipping egg whites to the exclusion of all other acids?

Virtually every single egg white recipe will say add some cream of tartar to egg whites to help them whip better because the cream of tartar will lower the pH and make it more stable. But if all it's ...
7
votes
1answer
2k views

Cooking Chemistry: lemon juice/soymilk buttermilk substitute turning bitter and 'rising'

I made a soup recipe the other night (mainly potato, spinach, and veggie broth) that called for buttermilk. I substituted soymilk and lemon juice, reading online that that was a good substitution for ...
7
votes
2answers
2k views

How do I calculate the final acidity of homemade vinegar?

I am making vinegar by mixing vinegar (containing the mother) and wine, and then allowing fermentation to occur. I am wondering how to calculate the final % acidity. Assume: I know the initial ...
8
votes
2answers
3k views

Do breadcrumbs really act as a binder in meat preparations?

I routinely hear that breadcrumbs are added to burgers and meatballs to bind them. For example, see the answers to this question: how to stop meatballs falling apart. On the other hand, I have heard ...
2
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1answer
275 views

Flavor and Chemical Composition of Thyme

What is the flavor of Thyme? What chemicals give it this flavor?
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votes
3answers
4k views

Dissolving Egg Shell

I know that an egg shell is made up of approximately 92% Calcium Carbonate. The remaining percentage of the mass is a protein matrix. I know that vinegar (5% acetic acid) dissolves the Calcium ...
6
votes
2answers
13k views

Why do uncooked frostings that contain milk not need to be refrigerated?

I have seen (and used) recipes for icing and glaze that use uncooked milk in them, yet they do not need to be refrigerated. (For example, one with powdered sugar, milk, vanilla and butter or ...
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vote
3answers
1k views

What chemical(s) gives molasses its flavor so that it is used as an ingredient?

I'm curious why there isn't a zero-calorie molasses substitute. The USDA nutrient database lists a bunch of minerals, but what is it that gives it the "taste" of molasses?
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votes
4answers
4k views

Why does strata have to come to room temperature before baking?

I've made strata a few times before, usually for brunches where I have a number of guests coming over and don't want to spend all my time in the kitchen. I always follow instructions in the recipe; I ...
0
votes
1answer
262 views

Is it possible to thicken frozen cream?

I know you can use frozen cream for cooking applications such as in gratin, but can I thicken the cream? By thicken, I mean making it into something like a bechamel sauce. Would I pour the cream in ...
9
votes
3answers
19k views

What is the purpose of oil or butter in bread?

Specifically in wheat and potato breads, what is the purpose of adding oil or butter to the dough? I have always assumed it was just for flavor, but I suspect there is some background chemical ...
11
votes
2answers
2k views

Coffee foam vs. Tea foam

One sign of really good fresh well-roasted coffee beans is foam. When you pour hot water into the French press, it foams, often forming a head up to 2" high. And when you use an espresso machine, ...