Is Aseptic the Same as Sterile? Brewery Microbiological QC

It can be challenging to figure out just how clean of an environment you need in a brewery. After all, you want something to survive and thrive – your beer. But you want to kill off any unwanted contaminants. This is where the question comes in, “is aseptic the same as sterile?”

In brewing, these two terms are not only not interchangeable but critical to differentiate between and work with separately.

What Does Aseptic Mean?

The word aseptic comes from the Greek “not toxic.” It refers to a product or an environment that will not harm you.

Typically, when we talk about aseptic, we are discussing foods and beverages. For example, yogurt should be aseptic as should fruit purées prepared to mix in your beer. The term aseptic can also be used in medical situations where the human body is involved.

For example, when you get a cut on your hand, you can clean it with antiseptic wipes to ensure all harmful living organisms are killed. You have then created an aseptic environment. This process is also used when an IV is inserted or surgery is performed.

The surface of the skin is cleaned to make it aseptic, but the human body is not killed, nor is any section of it. Life can still thrive, but toxins are eliminated.

To prepare an aseptic product or environment outside of the human body and medicine usually involves heat and then cold. The temperature is raised to well above the boiling point, which will kill off all harmful bacteria and toxins. Then the temperature of the food or beverage is quickly lowered, called cold crashing, to preserve any helpful bacteria or microorganisms.

Yogurt is an easy food to discuss when it comes to an aseptic environment. The yogurt is brought to high heat and then cooled quickly, killing off any harmful toxins but preserving a healthy environment for live and active cultures that create a healthy microbiome for humans.

What Does Sterile Mean?

Sterile, in contrast, means an environment that is entirely devoid of all living organisms, positive and negative.

You cannot have sterile food. You cannot be a sterile human. You cannot have sterile beer.

Creating a sterile living thing or previously living thing would leave it entirely devoid of all vitamins, nutrients, and healthy microbes that are good for the human body.

Boiled broccoli is one great example of a food that can be made sterile, but then loses all of its nutritional value.

When we boil broccoli to the point of softness, we leave behind up to 70% of the nutritional value. The same goes for all boiled foods.

You can still steam the food, or flash boil it, and retain nutrients, but that would be an aseptic food, not a sterile one.

We do want sterile conditions, however, when it comes to the production of foods.

For example, you want the kitchen in which your food is prepared to be entirely devoid of all living microorganisms. With the exception of the food, all surfaces, interiors, and tools should be entirely free of any life forms that could potentially infect the food being worked with.

We also want a hospital, an operating room, or a doctor’s office to be sterile. Because there is such a high instance of germs in these spaces, we hope to stop the spread before it starts, preventing people from needlessly getting infected by other people’s germs.

Thus, those medical spaces are often cleaned with products heavy in bleach and other harsh chemicals that completely wipe out all bacteria and virus spreading contaminants.

Aseptic vs. Sterile

When we differentiate between the two, we could say aseptic allows for healthy life to thrive without interference and sterile shuts down all living organisms, or as much as possible.

The aims are different – one to create a healthy living space and the other to destroy all life – so the approaches are necessarily different.

To create an aseptic environment, we use heat and sometimes light chemicals. To create a sterile environment, we attack with harsh chemicals extensively or use heat for long periods of time.

When Do You Need Aseptic in Brewing?

In brewing, then, we want an aseptic environment in the actual product. We do not want to destroy all life, all nutrients, and all vitamins, from the brew. We would effectively be shutting down almost all flavor and aroma.

Think about it – for thousands of years, women brewed beer in their homes to ensure their children would have something healthy to drink.

Beer served multiple purposes for entire families and was sometimes the only thing family members had to drink in a day because local running water was highly contaminated from toxins that entered waterways from up stream.

To create sterile beer would have been to destroy much of the purpose of drinking beer in the first place. Beer was rich in vitamins, minerals, and even probiotics – the healthy bacteria humans need in our guts to have overall healthy bodies.

While there are commercial breweries today that do indeed create sterile beer, boiling it, pasteurizing it, and filtering out all nutrients, most smaller, craft brewers harken back to the old days and trust in the good bacteria in beer to kill off the bad bacteria, and the alcohol to do the rest.

When Do You Need Sterile Brewing?

That is not to say that we don’t need any sterility at all in brewing.

We want entirely sterile surfaces, tools, and equipment so that we can indeed minimize the number of unwanted invaders in the beer, mostly because we want to prevent off flavors that can ruin a whole batch of beer.

So it pays off in spades to use bleach and other harsh cleansers when it comes to keeping your lines and your equipment clean, as well as all of your work surfaces.

In the end, we want a sterile brewing environment and an aseptic beer.

Cheers!

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Sources:

1. https://www.probrewer.com/production/ingredients/is-my-fruit-puree-aseptic-and-why-should-i-care/
2. https://www.pharmaguideline.com/2017/10/difference-between-aseptic-and-sterile-area.html
3. https://www.biofuelsdigest.com/bdigest/2019/06/25/importance-of-sterile-design-in-aseptic-fermentation-how-to-keep-from-getting-burned/

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