Although blast freezing and flash freezing are sometimes used interchangeably, the two freezing methods are not the same. I’ll explain the differences in this guide so you can always be sure when to use a blast freezer over a flash freezer and vice-versa.
What are the differences between a blast freezer and a flash freezer? The differences between a blast freezer and a flash freezer are as follows:
- Blast freezers don’t use cryogenics
- Flash freezers can freeze food into the negatives
- Blast freezers freeze food faster
- Flash freezers are for long-term food storage
In this guide, I’ll first delve into how blast freezers and flash freezers work individually, then explain the differences between the two appliances. If you’re wondering whether you need a blast freezer or a flash freezer, I’ll talk about that as well, so keep reading!
What Is a Blast Freezer?
Blast freezers or blast chillers are referred to as shock freezers as well. That name is fitting once you learn how a blast freezer works.
When you put food in a blast freezer, it rapidly brings down the temperature of that meal. It takes only a little over an hour (approximately 90 minutes) for food to cool down from 158 degrees to 37 degrees Fahrenheit.
No household freezer can reduce food temperature that quickly!
So what’s the point of a blast freezer, you ask? There are several purposes of this appliance, so allow me to explain them now.
Many foods and beverages should stay cold even if they’re not being served right away. By blast chilling a meal, it maintains its freshness and flavor.
One of the coolest facets (pun intended) of a blast freezer by far is that you can put a meal in while it’s piping hot and the freezer will still adequately cool it. It takes longer, but it’s doable.
Nothing ruins food faster than bacteria such as E. Coli.
Although most strains of bacteria that affect food will only cause food poisoning and other illnesses, no one wants to be sidelined with sickness if they don’t have to be.
Since bacteria replicate easily in environments where the temperature is between 46 degrees and 154 degrees, blast freezing prohibits the development of bacteria at the reduced temperature range it keeps food.
If you read my related article on blast freezing, then you might recall how it’s mostly commercial operations such as restaurants and catering businesses that use blast freezers. That’s because these units are often bigger than traditional refrigerators.
Household options are available, but usually for well over $1,000. Blast freezers are considered specialty appliances that the average person doesn’t need or can’t justify the cost of purchasing one.
What Is a Flash Freezer?
Next, let’s talk about flash freezers.
Flash freezing can quickly reduce food temperature in one of two ways: liquid nitrogen and other forms of cryogenic freezing.
Liquid Nitrogen Freezing
The first freezing method a flash freezer uses is exposing the food to liquid nitrogen, which has a base temperature of -320.8 degrees. Liquid nitrogen looks and behaves like smoke, sort of like what you’d get out of a Halloween fog machine.
In the culinary world, liquid nitrogen has been used in some way, shape, or form since at least 1890, when this liquid state of nitrogen was first included in a recipe book.
Today, restaurants use liquid nitrogen flash freezing for preparing frozen or cold foods and desserts, from ice creams to baked Alaskas and everything in between.
Since liquid nitrogen can cool food so rapidly, fewer ice crystals develop during cooling than they would when using traditional freezing.
This allows the food to maintain its smooth, creamy texture, which is especially important when serving delectable ice cream or sorbet.
Cryogenics might sound like something people will use in the distant future, but that future is here today.
A variety of cryogenic gasses–liquid nitrogen among them–can be used in food storage and transportation.
For example, in a truck traveling long distances, the frozen food would be packed with cryogenic gas to maintain the frosty temperature of the food.
Cryogenic freezing can also preserve a food’s temperature for extended periods, which is another aspect of its value.
What Are the Differences Between Blast Freezers and Flash Freezers?
Although at their most basic, blast freezers and flash freezers will freeze food, how they go about doing it and the duration are not the same. Let’s take a deep dive into the key differences between these freezer types now.
Blast Freezers Don’t Use Cryogenics
The rapid cooling of a blast freezer is completely cryogenics-free. Rather, a blast freezer has forced cooled air that generates when the freezer door is closed.
As the forced cool air blows out into the enclosed chamber, the food then begins to drop in temperature.
You can adjust the settings of the blast freezer depending on whether the food within is hot, chilled, or at room temperature, but the appliance freezes food in the same way nevertheless.
Flash freezers rely on cryogenics for rapid freezing. In most instances, the cryogenics used is liquid nitrogen, but other cryogenic gases are eligible for flash freezing as well.
Flash Freezers Can Freeze Food into the Negatives
The boiling point of liquid nitrogen is as low as -320 degrees, so you can reliably expect that a flash freezer using liquid nitrogen can freeze food to at least that temperature.
Food will freeze in temperatures under 40 degrees, so when you consider that there’s a difference of more than -200 degrees between that temperature and the temps that liquid nitrogen in a flash freezer can achieve, it might be a bit much.
At least you don’t have to worry about your food thawing prematurely!
Blast freezers, by comparison, freeze food to a more reasonable degree, reducing the temperature to 37 degrees.
That temperature is only barely under the range of 40 degrees, so while your food is sufficiently frozen, it won’t be nearly as frozen as flash freezing the same food.
Blast Freezers Freeze Food Faster
There is a benefit to not bringing down a food’s temperature into the negatives (let alone the negative hundreds): faster freezing.
As you’ll recall from earlier, blast freezers can freeze food to 37 degrees from more than 120 degrees in only 90 minutes. That’s right, an hour and a half.
The process isn’t instant due to the forced cooled air that blows in the blast freezer. The air must circulate several times.
How long does it take to freeze food with a flash freezer? At least a couple of hours.
Flash Freezers Are for Long-Term Food Storage
Cryogenically freezing food creates a much lower temperature that’s conducive to long-term cold storage for food.
Restaurants can pre-plan, ordering ingredients and then stashing them in a flash freezer for days or even weeks.
As you’ll recall, since instant freezing reduces the rate of ice crystals (which is true of blast freezing as it is flash freezing, by the way), there’s no need to worry about the appearance and condition of the food after freezing.
Long-term cold storage also comes in handy for transporting cold food across long distances, as I touched on above.
Which Is Right for Me – A Blast Freezer or Flash Freezer?
I want to stress that both blast freezers and flash freezers are not everyday appliances. The average homeowner doesn’t need either type of freezer because its inclusion would be extraneous.
Blast freezing and flash freezing mostly come in handy for cold-storing mass quantities of food or ingredients. That’s something the average person does not have to do.
For those in the restaurant or catering industries (including home catering), choosing between a blast freezer or a flash freezer can be difficult. Both appliances do roughly the same job, and they’re sized about the same.
It also doesn’t help that if you try to do a modicum of research online, blast freezers and flash freezers tend to get confused for one another or used interchangeably.
Between the two appliances, I would recommend a blast freezer more for restaurant or catering use. There are several reasons for this.
First is the speed at which blast freezers work. In some instances, it can take a blast freezer several hours to fully freeze food, such as if you put a meal into the freezer piping hot. For room temperature or already cool food though, it’ll be completely frozen in a little over an hour.
Flash freezers, as I talked about earlier, are not quite as expedient.
Another reason a blast freezer is more fitting is that it doesn’t use liquid nitrogen. I’m not saying liquid nitrogen is unsafe, but for someone who’s inexperienced with it, you could put your health at risk.
Breathing in liquid nitrogen, for example, can cause symptoms such as vomiting, nausea, and dizziness. In serious instances, you can fall unconscious; death can occur as well.
Blast freezers only use forced cooled air, so even if you did take a big mouthful of it (not saying you should, only that you could), you wouldn’t have any adverse effects except feeling very cold.