Yeast vs. Mold

Yeast vs. Mold

Have you smelled or seen something odd in your home? Are you chasing down smells and unsightly trails of colorful fungal growths? When it comes to fungus in the home, there can be confusion between yeasts and molds. While both are types of fungus, they play different parts in the fungal ecosystems.



Yeasts, like mold, are a member of the fungus family that can be found in nature as well as in a home. Unlike mold, however, yeasts are also cultured for industrial use, such as those used in the kitchen to ferment.

Yeasts are a unicellular structure, meaning they have only a single cell, and these single yeast cells are considered to be an organism. Yeasts, however, can vary and obtain multicellular structures in some cases.  Yeasts multiply new identical bodies from the single-cell it originally derives from to reproduce and grow across an area. Similar to the way twins are created in the womb, this, now multicellular yeast organism, is made of entirely identical cell structures.

Yeast is typically colorless and smooth to the touch; however, in some cases, yeasts may appear white or thread-like. In the beginning stages, yeasts can be hard to distinguish from the matter it grows upon due to the lack of color.

For growth and nourishment, yeast requires an organic host. In its natural environment, yeasts will grow prominently on plants and in soil. Yeast is attracted to sucrose-rich products and can also be found often on fruits and vegetables during the natural fermentation process. Yeast can also grow on and in humans and animals. The most common yeast found on and within the body is called Candida. At normal levels, this yeast is not problematic; however, should an overgrowth occur, unpleasant symptoms may arise. An abundance of yeast in the body can cause female reproductive infections, itchy dry skin, including triggering symptoms resembling athletes’ foot, and gastrointestinal issues resulting in unpleasant bowel movements. In most cases, an antifungal medication or cream can cure the yeast infection. However, a physician’s official diagnosis and treatment is required.

While the growth of yeast may be considered unpleasant, there are also benefits of yeast in nature and your home. Nutritional yeasts are used in brewing and baking, providing us with bread and beer. Naturally occurring yeast within the body, at normal levels, assist in the balance of bacteria along the digestive system.



As aforementioned, molds and yeasts alike are a member of the fungal family and feed on organic materials to survive. Unlike yeasts, molds are a complex multicellular organism. When molds begin to colonize the cells reproduced are the same structure, like yeast. However, while yeasts individual single cells are considered organisms, each mold colony is deemed to be separate organisms.

Molds are usually more natural to identify than yeasts. However, in the initial stages of mold growth, when single mold spores are present, the naked eye cannot visualize the mold as the spores are microscopic. Once the colony is formed, you may visually notice the mold. There are thousands of species of molds which all have different characteristics. Some species may appear slimy while others appear fuzzy or hairy. The same is true for the color of mold, orange, yellow, green, brown, white, and black are all possibilities. See our previous blog for a more in-depth look at the different mold colors and species.

Molds can also occur naturally like yeasts. However, molds require the right conditions to do so. With organic matter present for nourishment, in warm moist environments, molds thrive.  In the house, should a plumbing incident occur or a leak in the garage, mold would begin to grow at a rapid rate due to the humid Florida climate and water combination.

While molds can be dangerous, even toxic, to those around it, some molds have benefits for our daily lives and nature around us. When vegetation dies in the wild, mold grows and feeds on the substance to break down this matter and assist in its reabsorption in the earth. Mold is also a vital role when making cheeses, such a blue cheese. And finally, without mold, we would not have some of the most powerful medicinal breakthroughs around the world, including the famous penicillin.


While yeasts and molds hold similar properties and both carry pros and cons with its presence, invasion of either of these two fungi are unwanted on the home front. For a professional look into what is growing inside your home, set an appointment today!

Published: February 24, 2020
Author: Mold Inspectors of Florida
Categories : Uncategorized