Fascinating question.

Let's start with bread. There are actually multiple ways to make bread which could change the ingredients used. However, there are some primary ingredients that go into most breads. First is yeast, the essential ingredient that makes bread dough rise and gives bread its delightful taste and aroma. Yeast alone will not activate to accomplish its bread-making reactions. Yeast are tiny living plant-like organisms. They require activation by warm liquid (usually water or milk) and feeding by sugar or starch. The combined result is that the yeast releases tiny bubbles of carbon dioxide (CO₂) gas, that gas being what makes the bread rise. The added liquid (water, milk, buttermilk, cream, or juice) is important for two reasons. First, is dissolves and activates the yeast. The ideal liquid temperature is 100-110 degrees Fahrenheit. Too cool a liquid and the yeast reaction stops or happens too slowly; too hot a liquid and the yeast will be destroyed and not create CO₂ bubbles.

Second, the liquid mixes with flour to create a sticky and elastic dough. The added sugar (cane sugar, brown sugar, honey, molasses, or jam) feeds the yeast, adds flavor, and creates some of the brown coloring of the bread's crust. So, bread requires yeast, warm fluid, and sugar.

Next, bread requires flour. Most commonly a wheat-based flour is used. However, flour can be ground from a variety of foods such as, spelt, rye, buchwheat, oats, corn, rice, garbanzo beans, almonds, etc. Wheat is rich in gluten, a substance made of proteins, which gives bread dough its elastic texture and strength. The strong gluten network in wheat flour is what traps the CO₂ bubbles, creating the light, fluffy volume of bread. Gluten also causes the browning of the bread crust when baked. That's why gluten-free breads tend to be denser.

The remaining ingredients are salt, eggs, and fat. Salt is also an important ingredient. Salt enhances the bread volume, by tightening the gluten structure and adding strength to the dough. Salt also slows the rising time, enabling the bread to develop more flavor. Most recipes use eggs because they add richness and protein, enhance the flavor of the bread, and add color to the bread. Eggs also help make the crust tenderer and the bread texture lighter. Eggs are a leavening agent, meaning they help the bread rise. Eggs are what make angel food cake so tall and fluffy. Interestingly, egg yolks contain lecithin, a fat that is required in the cells of our bodies. Lecithin is used for treating memory disorders like dementia and Alzheimer's disease. Finally, fat is added for flavor, tenderness, and moistness. Fat slows moisture loss, which helps the bread stay fresh longer. Types of fats used include butter, margarine, shortening, or oil.

Hand sanitizer is slightly more complex for its ingredients. Most hand sanitizer is alcohol-based, but some non-alcohol based versions also exist. I will only focus on the alcohol ones here. Alcohol has been widely used as an antiseptic, or antimicrobial substance, since the late 1800's. Alcohol-based versions usually contain some combination of the following: isopropyl alcohol (chemical formula: C₃H₈O), ethanol (or ethyl alcohol, chemical formula: C₂H₅OH), or n-propanal (chemical formula: CH₃CH₂CH₂OH) in concentrations ranging from 60% to 95%. The rest of the ingredients depend on the brand recipe, and include humectants, moisturizers, emulsifiers, fragrances, and colorants/dyes.

Humectants are chemicals that attract moisture to the skin surface. Most commonly the used humectants are glycerin and propylene glycol. These help prevent your skin from drying with frequent use of hand sanitizer. Moisturizers help seal the skin surface and make skin smoother. Common moisturizers include isopropyl myristate (a chemical substance found naturally in nutmeg, coconut oil, and some animal fats), aloe vera, and tocopherol acetate (synthetic vitamin E). Emulsifiers are binding agents to help prevent the other ingredients from separating and thickening the hand sanitizer into a gel. Carbomer and amniomethyl propanol are frequently used. Beyond those, different brands may have added fragrances and colorants to make their products distinct from competitors.

Bread is very simple. It only NEEDS two ingredients: flour and water. If you mix flour and water, and let it sit for a long time (several days), it can make a nice fluffy bread dough. Then, you bake it in the oven and get bread.

You only NEED two ingredients, but most bakers choose use at least FOUR ingredients: Flour, water, yeast, and salt. Yeast makes the dough get fluffier faster. Salt makes it taste better. Some bakers also add fruits, nuts, or seeds to make the bread taste better.

Details:
If you use just flour and water, you need to let the ingredients sit out for a long time so that little microorganisms (especially yeast) from the air naturally start to grow in the flour and water. The yeast naturally creates little bubbles of carbon dioxide in the bread dough, making the dough grow in size. This is what makes bread fluffy once it is baked. You can speed up this process by adding yeast from the grocery store.

Hand sanitizer is also very simple. Its job is to kill viruses and bacteria on your hands that can make you sick. To do this, it only requires ONE ingredient: alcohol. Most hand sanitizer companies also add other ingredients to make it feel better on your hands, like water, aloe, and scents to make it smell good.

The ingredients in bread depend on the type of bread. The absolute most basic bread can be made with only a flour and water. The flour is typically wheat, but others, such as cornmeal, will also work. This will make an unleavened bread, not the loaf type that is sliced to make sandwiches. The classic example is matzah.

To get a loaf-type bread, one must add a leavening agent. Basically, this is anything that causes gas bubbles to form. Yeast is used in breads which are allowed to sit for some length of time to rise. Yeast is a microorganism which produces gaseous carbon dioxide as it grows . Chemical reactions can also be used to produce the necessary gas, such as with baking soda and baking powder. Breads made with chemical leaveners are called "quick breads", because the lengthy rising step is omitted. In addition, the dough must be able to trap those bubbles. Most breads use wheat flour because wheat contains a protein called gluten which forms a stretchy network well-suited to catching the gas. Recipes without gluten require some other ingredient to form an analogous network, commonly eggs and gums.

Beyond the basics, many ingredients can be used to influence the character of the final product. Sugar will make a bread sweeter, but also change the texture; salt enhances flavors and helps control yeast growth ; fats help with texture; pretty much anything can be added for flavor.

The most effective hand sanitizers use alcohols, specifically ethanol and isopropanol as germ-killing ingredients. The alcohol basically dissolves the outer membrane of bacterial cells, causing the cells to rupture and the cell to basically explode (or at least fall apart). Other gels, scents, etc. may be added to make the product more appealing though.

The main ingredients in bread are flour, water, and yeast. The active ingredient in hand sanitizer is ethyl alcohol with water and glycerin added to make a gel. You can read the labels on both for a complete list of ingredients. Bread often has ingredients to make it taste better or last longer. Hand sanitizer has a lot of ingredients that affect its consistency and shelf life as well as fragrances.

You can read the labels on products to find their ingredients.

Here's a recipe for yeast bread:

Here's something about the ingredients in hand sanitizer:
The active ingredient in hand sanitizer is usually an alcohol. The U.S. Food and Drug Administration and the Centers for Disease Control recommend ethyl alcohol, isopropyl alcohol or a combination of both in concentrations ranging from 60 to 95 percent. Alcohol is an antimicrobial that kills bacteria. Benzalkonium chloride is another FDA-approved active ingredient in some hand sanitzers. Although it is not an alcohol, benzalkonium chloride also works to kill bacteria and some viruses on the hands.

hand sanitizers

Bread is made from wheat flour, and is fermented with bread and beer yeast. Typically bread also contains some salt. The yeast requires water to do the fermentation, so you need to add water to make it.

Hand sanitizer depends on the brand. I am to understand that hydrogen peroxide (H₂O₂) is a common component.

People across the world make different kinds of breads with different ingredients, and different cultures may have different definitions for the word "bread".

For the sake of our immediate question, let us define "bread" as the type of food made with flour and water, allowed to rise, and then baked for consumption. This kind of bread can have as few ingredients as three: flour, water, and yeast, or as many as the following: flour, water, yeast, sugar (such as white sugar, molasses, honey, and so on), butter or shortening (or other types of fats), nuts and seeds, fruits (bananas, etc.), potatoes, eggs, and fillings (vegetables, meats, sweet pastes).

The types of "bread" that are unleavened (not risen by yeast) can have even more ingredients. The bread we buy from the supermarket commonly has flour, water, sugar (any kind of corn syrup), salt, dough conditioners (to improve texture, mouth-feel, etc), preservatives, and flavors coloring agents. The conditioners are added to make the bread taste a particular way, the preservatives to make bread last longer, and the flavors and colors are added to make bread taste and look a certain way, usually a way that makes us want to buy more and eat more. You will see these ingredients listed on the plastic bags. Not all these additives are harmful to us, but many can have undesired long-term effects on our bodies.

Hand sanitizer usually has some form of alcohol - not the same as the kind we drink - or a substance called benzalkonium chloride, to kill bacteria. In addition, hand sanitizer also has substances that prevent our hands from drying out too much (alcohol dries skin), and these are called humectants. Most sanitizers also have ingredients that moisturize and make skin smoother, and ingredients that help the sanitizer mixture stay mixed. Many sanitizers also have coloring and fragrance. If you're curious, you can always find the names of the fragrance or coloring on the ingredients list on the sanitizer bottle.