The more you try to change a recipe, the more you understand how much science is involved. I often find myself googling random things to see if I can adapt a recipe a certain way, then I forget the information I just learned and repeat the cycle over and over. I have collected the following in order to build off the curiosities I have had rather than having to look them up again and again.

Conversions

Conversion calculator

Butter

• Butter in the US is 80% fat, 18% water, and 2% milk solids. European butter has 82% fat.
• To replace butter with coconut oil, 70% coconut oil and 3% milk solids is a good start. You may or may not need the additional 15% water/milk.
• To replace butter with liquid oil, use 75% oil.

Baking soda/baking powder

• Both baking powder and baking soda are used for leavening.
• Baking powder is baking soda plus the acid needed to interact with it to make it rise.
• Baking soda is used when the mixture already has an acidic component (ex. lemon juice or buttermilk), whereas baking powder is used when there is not an acidic component. Recipes that call for both usually need the added leavening from the baking powder since the baking soda will react with the acid.
• Baking powder is double-acting, so it will rise when initially combined with liquid and again when heated.
• Baking soda helps baked goods brown better by neutralizing acids, turning them alkaline, and encouraging browning.

White whole wheat (www) flour

• Add 2 tsp. more liquid per cup of flour when substituting white whole wheat for all-purpose flour.
• Can use a small amount of orange juice to balance out wheat flavor, sub for ~1 1/2 Tbsp. liquid per cup of flour.
• When baking bread with www, let dough rest for 30 minutes with all liquid ingredients, yeast, and ~80% of the flour before kneading.
• Www flour works fine for yeast doughs, cookies, etc. Not great for cakes and light baked goods.
• Www will add a bit of color to final baking.

Milk

• Soy milk is the best non-dairy milk substitute for milk or heavy cream since it has the closet protein content to whole milk. It also has a lot more flavor than most other milks.

Eggs

• To substitute 1 egg, use 1 Tbsp. flax meal + 3 Tbsp. of water.

Bread

• Kneading bread is better for a tight crumb and lower hydration. Stretch and fold is better for open air pockets and higher hydration.
• For a single, standard-sized loaf of bread, use ~1 cup of mix-ins.

Cookies

• If baking chilled cookie dough, preheat oven to 360°F, then turn it down to 350°F when the cookies go in the oven. This will help ensure the oven is hot enough and avoid under-spreading the cookies.
• For crispier cookies, bake 10° hotter and/or a couple minutes longer than originally called for.
• Cookies are ready to be removed from the oven when the center is not completely set but no longer looks wet.
• Rolling cookies in sugar reduces the spread.

Cookie spread

Cookie ingredients

• Cornstarch: adds softness. This is like a bakery cookie that has no crispy edges and probably not a lot of color 
• Oil/fat: adds crisp and spread. If there’s too much, it will be greasy and the edges will lattice out
• Egg white: adds air and structure. This doesn’t necessarily mean softness, just more bubbles. 
• Egg yolk: adds fat, flavor, and chew. Instead of adding air like egg whites, the yolk makes the cookie denser. 
• Sugar: spread and softness. Brown sugar adds softness 
• Baking soda: spread and browning
• Baking powder: puffier

Brownies

• To make crinkly tops on brownies, the sugar has to be fully dissolved and there has to be 100-200% sugar to water in the recipe (this includes the eggs). Using powdered sugar is the easiest and most foolproof way to achieve this.
• Recipes use either melted chocolate or just cocoa powder to achieve the chocolate flavor. 
• Espresso powder can be added to deepen the chocolate flavor. 
• The texture can be categorized as cakey or fudgey. Cakey is light and fluffy while fudgey is dense. Fudgey can be categorized further as chewy or not chewy. 
• Baking in a dark metal pan yields the crispiest edges.