How Blenders Work


Got a hankering for a sweet, frozen smoothie? A blender's just the thing. See more pictures of appliances.
Howard Shooter/Dorling Kindersley RF/Getty Images

­Say you want to turn the contents of your market's produce section into a frothy breakfast drink. Or maybe you're craving a refreshing frozen cocktail to combat the summer heat. Or perhaps you need to dislodge phage particles from bacterial cells. What do chefs, bartenders and geneticists have in common? They all use blenders. In the kitchen, a blende­r is the appliance you can't live without if you want to turn solid ingredients into liqu­id deliciousness -- from smoothies and shakes to salad dressings and soups.

Blenders were invented in the early 1900s to help meet the demand for malted milk drinks, which physicians prescribed to help build strength. Blenders quickly made their way into soda fountains as a method for whipping up ice cream concoctions. However, it wasn't until 1937 that the blender found the popularity it has today as an indispensable vehicle for mixing up cocktails. Fred Waring, the leader of the big-band TV and radio stars "Fred Waring and the Pennsylvanians," took an interest in the blender as a means to make drinks for a raw food diet he had been prescribed for an ulcer. He founded the Waring Company, which funded the development and manufacturing of an improved version of the blender. Waring marketed it as the Miracle Mixer, an essential tool for making daiquiris. Renamed the Waring Blendor, this revolutionary invention was used by Jonas Salk when he developed the vaccination for polio. It soon caught on as a "liquidizer," useful for making health food drinks for special diets. And a frozen margarita wouldn't be the same without it.

­Blenders are versatile appliances that have a variety of uses in the home, business and laboratory. T­he main function in home and bar use is geared toward crushing ice. Blenders also liquefy and emulsify softer food ingredients, such as fruit and yogurt, which results in a thick consistency and a smooth texture. You can find commercial blenders in plastics manufacturing plants, where they blend various powders and dry materials. Blenders also have a place in the lab for research in industries such microbiology, where researchers use it to extract bacteria from samples.

So what should you look for in a blender, and what's behind that smooth swirl that appears when your blended beverage is ready to drink? Find out on the next pages.

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Blender Mechanics

The parts of the blender, from top to bottom, are the lid, jar, blades, gasket, jar base and housing.
The parts of the blender, from top to bottom, are the lid, jar, blades, gasket, jar base and housing.
© iStockphoto/rolf bodmer

The individual, and often replaceable, components of a blender are pretty basic and consist of the following:

  1. Housing
  2. Blade
  3. Jar
  4. Gasket or seal ring
  5. Jar base or jar nut
  6. Lid

In a knee-bone-connected-to-the-shin-bone sort of way, here's how the parts work together. The base of the blender is the housing, which contains a high-speed, fan-cooled electric motor as well as the speed controls. The hefty weight of the housing keeps the blender on the counter during blending. In some models, the blade is permanently attached to the housing, but in most cases, the blade, gasket and jar base are all separate pieces that fit together and attach to the jar. The blade sits inside the gasket, which prevents leakage. These two parts fit snugly into the jar base, which screws onto the jar.

The assembled jar snaps onto a coupler, also known as a clutch or a serrated drive, depending on the manufacturer, which protrudes from the housing and attaches to the blade. The coupler connects to the motor, and this is the device that controls the movement and speed of the blender.

The lid forms an airtight seal on the jar -- prepare to wipe down your walls, counter and floor if you forget the lid on a full blender. The lid usually has a removable piece called a fill cap, which allows you to add ingredients without stopping the blender. In some models, this piece serves a dual purpose as a measuring cup.

The blades of a blender are constructed of stainless steel for durability and maximum sharpness. Most configurations consist of four blades arranged in multiple planes and set at different angles. This results in more contact between the food and the blades. The shape of the jar plays a part in the blender's efficiency, too -- tapered jars, the most effective shape, funnel food down into the blades.

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­­To explain what happens to your food when you blend it, let's follow the path of a strawberry that you drop into the jar with other­ ingredients to create a delicious smoothie. You push a button to start the blender, and the motor begins to turn the blades. The circular whirring motion creates a vortex, defined as a spiral movement in a fluid. In the blender, the fluid includes both liquid ingredients and air. The vortex causes a vacuum at the center of the jar, which pulls the strawberry toward the middle, much like a tornado. Unlike a tornado, though, a blender jar contains the vortex.­

As the strawberry combines with the other ingredients and begins to liquefy, the liquid follows the blade in a whirling motion around the container, forming a well near its center. The well in the center of a blender's vortex is shallow, so it displaces the blender's contents as they're drawn toward the axis at the center of the blade. The whirling motion and lack of space below the blades forces the liquefied strawberry up and out the sides. This circular pattern continues, whipping air into the contents, which helps mix the ingredients more quickly, until you stop the blender. The final result is a frothy strawberry smoothie with a homogenized blend of ingredients and a consistent texture.

In our next section, we will talk about what makes one blender different from another and what to look for when shopping for one.

Types of Blenders

Like a countertop blender, an immersion blender uses blades to turn solids into liquids.
Like a countertop blender, an immersion blender uses blades to turn solids into liquids.
© iStockphoto/Alexandra Draghici

­In their vast number of makes, models and options, blenders are a lot like cars. Make a trip to the local appliance store, and you'll find models that range from the Hyundai of blenders, with a 450-watt motor and a white plastic base, to the Mercedes of blenders, with a 750-watt motor and stainless die-cast base with­ digital controls. The main features that differentiate one blender from another are motor speed, controls and design.

Manufacturers typically indicate blender motor speed in watts and occasionally in horsepower -- 1 horsepower equals 746 watts. The majority of household models fall within 500 to 750 watts, though options range from 300 to as high as 1,500 watts. High wattage blenders often cost more than their low watt counterparts, so it may seem like more expensive equals a better blender. But consumer reviews contradict this theory. Tests performed on a wide sampling of blenders conclude that wattage has little correlation to performance [source: Consumer Search].

The wattage number displayed by the manufacturer measures the power consumed by the blender motor. But the power generated by the motor is what dictates performance. You want enough initial torque -- the force that causes rotation around a central point -- to keep the motor from straining when it meets resistance. Since manufacturers don't disclose any of this information, the best way to determine the best blender for your needs is to read consumer reviews, which are readily available for many blenders on the market.

Blender controls are another differe­ntiating factor from one model to another. While experts say that a three-speed (low, medium, high) blender will do everything you need it to, a good number of blenders offer seven or more speeds, helping you choose whether you need to chop, puree or liquefy. Some even expand beyond functions, suggesting speeds for juices, sauces or milkshakes.

Beyond wattage and controls, the feature that often distinguishes one blender model from another is the jar. Blender jars come in three materials -- glass, polycarbonate and stainless steel. Which one to use largely depends on your personal preferences. Glass jars are more prone to breakage, but their weight gives them more stability. They're also scratch-resistant and less likely to retain odors. Polycarbonate jars are lighter and won't shatter if dropped on the floor, but they are prone to scratching and can end up smelling like their contents. Stainless steel is sleek and modern, which makes it aesthetically pleasing, but you can't see inside, so you have to stop the blender to see if everything's liquefied. In addition, glass and plastic usually have markings you can use to measure ingredients directly into the jar, but stainless doesn't.

In terms of design, blenders have come a long way in the past 100 years. Current styles range from no-frills basic to modern to retro with many looks in between. It's safe to say that there are many options to suit your style while adequately attending to your blending needs. To ensure that you don't end up with a blender that exudes fashion over function, be sure to check consumer reviews.­

Next, we'll break down some things to consider when determining what blender suits your needs.

Shopping for Blenders

­If you pore over research on blenders, you'll find many opinions of what makes a better blender. Often a blender will perform well in professional testing, but user ratings sometimes disagree. To get the best bang for your buck, do a little research on your own. Start by figuring out exactly what type of blender you really need. How often you will use your blend­er? Are you looking to mix up the occasional margarita, or do you want to spin out soups for a family of six? If you plan to blend sparingly, a budget pick is a safe bet. But if five smoothies a day keeps the doctor away, you may want to invest in a heavier duty model.

Next, consider how you'll use the blender. A key feature of the blender is its ability to crush ice. For the smoothest frozen drinks, seek out reviews that boast white snow with no icy chunks. Or if your ambition is to serve a silky smooth gazpacho, look for reports of a lump-free puree.

Durability is a big consideration. A plastic housing is generally less expensive but may be more prone to chip or­ break compared to its metal counterpart. Also, the motor should be mighty enough to blend a number of applications for several years without slowing down or puttering out.

Here are some other tips to keep in mind while you shop:

  • Consider a removable blade. Blenders with nonremovable blades are less likely to leak but are much harder to clean.
  • Certain blenders are designed to be less noisy, so if you have a newborn baby or a light sleeper in the househol­d one of these models is probably worth looking into.
  • If you don't want to clean your blender with a cotton swab, you may want to avoid one with push buttons. Touch pads and switches are easier to keep clean.
  • Appearance is important if you have limited storage and the blender needs to stay on your counter. There are many options to match the style of your décor.

If you want bells and whistles such as a touchpad, programmable controls or designer styling, you can expect to pay more than for a basic model with plastic housing and push buttons. But remember -- the most expensive blender isn't necessarily the best one.

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Sources

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  • Long, Tony. "Sept. 20, 1952: Kitchen Blender Pegs DNA as Stuff of Life." wired.com, September 20, 2007. http://www.wired.com/science/discoveries/news/2007/09/dayintech_0920
  • Sherer, Mike. "Blender bonanza: with more power and less noise, today's blenders showcase new features for mixing up profitable drinks." Cheers, June 2007. http://findarticles.com/p/articles/mi_m0BQE/is_/ai_n27294240
  • Windelspecht, Michael. "Genetics 101." Greenwood Publishing Group, pp. 35-36
  • Powder and Bulk Engineering - Professional Journal. "Removable Agitator Ribbon Ensures Pure Additive Blends." CSC Publishing, pp 1-2. http://www.lab-mixers.com/how-to-select.asp