What transpires if you add too much?
If you’ve ever been to a lab or museum and marveled at a perfectly preserved eyeball or a small dead creature floating in a glass container, you’ve seen alcohol’s ability to preserve things. This method is officially known as fluid retention. Since the 1600s, scientists have relied on it to keep their intriguing findings. According to the American Museum of Natural History, it can also support a sample for hundreds of years if done properly.(opens in new tab). You’ve probably seen how alcohol can keep objects if you’ve ever visited a lab or museum and gazed at a perfectly kept eyeball or a tiny dead creature floating in a glass container. Officially, this approach is known as fluid preservation. It has been used by experts to preserve their fascinating discoveries ever since the 1600s. The American Museum of Natural History claims that if done correctly, it can also sustain a sample for hundreds of years.(opens in new tab).
But how does it function?
The long and the short of it, according to Bill Carroll, an associate professor of chemistry at Indiana University Bloomington, is that it is toxic to the types of microbes that would lead to decay. He gave the analogy of vino. It is created when yeast consumes grape sugar and then excretes alcohol. However, he claimed that because the yeast excretes so much alcohol, the quantity turns toxic and destroys the yeast. According to the California Wine Advisor, wine’s 14% alcohol concentration helps prevent the bacterial development for years (many wineries also contain extra preservatives like sulfur).(opens in new tab).
According to Katherine Maslenikov, the curator of the fish archives at the Burke Museum in Seattle, a greater alcohol concentration is necessary to preserve other organic material, including DNA, tissues, or even complete creatures. Maslenikov frequently uses ethanol, a type of alcohol, for long-term preservation. A higher alcohol percentage is required, according to Katherine Maslenikov, keeper of the fish records at the Burke Museum in Seattle, to retain other organic material, such as DNA, tissues, or even whole animals. For long-term preservation, Maslenikov commonly employs ethanol, a kind of alcohol.
To halt internal biological processes like enzymatic reactions and tissue deterioration, Maslenikov, for instance, might take a specimen of a fish, extract some tissue samples for DNA analysis, and inject the fish with formalin. She might then place the fish specimen in a container containing 30% water and 70% alcohol. “70% seems to be that magic number” for long-term preservation, Maslenikov said. According to her, the solution contains enough alcohol to prevent bacterial and mold development as well as enough water to keep the tissues hydrated and help the animal or specimen maintain its form.
Even more concentrated alcohol, like 95% ethanol, acts as a dehydrator by removing the water from the cell, tissue, or whole-body material and replacing it with alcohol. According to the Ask a Biologist(opens in new tab) blog series operated by Arkansas State University, the absence of water alters water-sensitive proteins, which unfold, or denature, and harden in position next to one another, setting the specimen’s form. According to a 2013 research published in the journal PLOS One, this method is frequently used to preserve DNA.(opens in new tab).
Choosing an alcohol proportion can be challenging. Using too much or too little can have an impact on the sample’s elasticity and form, as well as reduce its ability to stay in the solution. Dehydrating a specimen in alcohol at high quantities will protect it. Maslenikov, however, noted that this procedure could also render an object fragile and shriveled (due to water loss). (from the hardened proteins). Depending on what you are attempting to protect, that can occasionally be acceptable.
In the meantime, if an organism holds on to too much water, it might degrade rapidly. In the interim, a creature may deteriorate quickly if it retains too much water.
Christopher Rogers, an assistant research professor at the Kansas Biological Survey and Center for Ecological Research at the University of Kansas, said in an email to Live Science that if a creature has enough water in its tissues, it can dilute the alcohol. In this case, it’s possible that the alcohol concentration won’t be strong enough to eradicate any hidden microbes that may be present in the specimen’s deeper regions, such as the intestines of a whole-animal specimen. The specimen can decompose if those microbes are overlooked. It is crucial to switch out the alcohol soon after marinating the animal because it increases the alcohol content in the solution, according to Rogers.
According to Carrol, there is a sweet spot for alcohol concentration when used as a preservative: “A concentration such that you inhibit microorganisms, but not destroy the cell structure of what you’re looking at.” “A concentration such that you inhibit microorganisms, but not destroy the cell structure of what you’re looking at,” says Carrol of the ideal alcohol content for preservative use.