Coffee drinkers the world over wake every day to the lilting sounds and the rich aromas of their favorite coffee brewing. Whether it be drip, French press or single-serving; black or with milk; espresso, latte, or cappuccino, nothing is more satisfying than that first sip of hot, delicious coffee.
Yet how many coffee aficionados have the satisfaction of knowing that their coffee would not be near as yummy if it weren’t for vacuum? Over the last two centuries, vacuum and vacuum pumps have become vital products in the coffee industry. And the benefits that they provide may surprise you. There are four major ways that vacuum is used to improve coffee production—freeze-drying, roasting, packing, and brewing. Read on for all the aromatic details.
Freeze Dry your Drip
The basic technique of freeze-drying can be traced back to the Incas in the 15th century. They would store their crops in the high mountains around Machu Picchu, where cold temperatures would first freeze the food, and then the low air pressure at high altitude would allow the water inside it to slowly evaporate.
Much more recently, in World War II, blood supplies were freeze-dried in order to keep them stable during transport without refrigeration. Since then freeze-drying has become popular in various applications, including pharmaceuticals and food. Freeze-drying allows the food to keep its natural chemical composition as well as its vitamins and minerals.
Freeze drying coffee before packaging helps maintain quality and freshness and keeps the all-important aroma of the coffee intact. Modern freeze-drying is only made possible by using modern vacuum pumps because the freeze-drying process takes place under vacuum.
Freeze-drying using vacuum relies on a process called sublimation, where ice skips the liquid phase, and turns from solid to gas. To start, coffee is spread out on sheets, frozen, and then placed in a drying chamber. Vacuum is then applied to the frozen coffee to remove the “free water” by reducing the air pressure, similar to the way altitude was used by the Incas). Sublimated water vapor is suctioned out by a vacuum pump and placed in another chamber. After the primary drying, it will then receive a second drying process to remove strongly bound water.
Roast with the Most
Vacuum pumps can also be used during the roasting process to dry roast the beans under vacuum. The result is reduced moisture without over-heating the beans during the drying phase of the roasting process. This changes the flavor of the coffee and reduces the “burn” of the bean as well as reduces the amount of the chemical acrylamide in the coffee. Coffee can taste more flavorful using this method.
Seal your Sumatra
The third use of vacuum in the coffee industry is in the packaging. Coffee packaging can be traced to France in the early 1700s, and the first coffee cans were invented in London in the early 1800s. Over the next 50 years, the roasting and packing industry advanced quickly, adding better and faster ways to increase production, freshness, and ship-ability.
Vacuum came on the scene in 1900. R. W. Hills of Hills Brothers invented a vacuum packing method to remove the air and keep the beans fresher longer. But vacuum packing didn’t provide a complete solution to fresher coffee. The problem is that after the coffee is roasted, it releases carbon dioxide gas for days (or even weeks). Darker roasts and shorter roast times tend to lead to more gas released. So if coffee is packaged quickly to keep it fresh, the buildup of carbon dioxide can make the packaging burst. (Yikes!)
One solution is to “rest” the coffee in the open air. But, as was discovered, oxygen causes oxidation which has been proven to quickly erode the aroma that helps make coffee so pleasurable. Another alternative is to puncture a small hole in the packaging…but again…O2 gets in after the CO2 goes out.
Then in 1960, an Italian company called Goglio invented a one-way degassing valve that allowed pressurized gas from the package while preventing outside air from coming in. This valve works like a vacuum, sucking the air out. Degassing values are still very popular in the coffee packaging industry today, and can be seen on many higher-end coffees. Vacuum-packed coffee will last for up six months, however, coffee experts agree that the flavor starts to degrade after two weeks. Storing them in the freezer will increase the longevity of the beans.
Vacuum your Brew?
The final use of vacuum in coffee is in the brewing process itself. For avid coffee drinkers, the universal question will always be, “What method of coffee brewing is the best?” Of all of the different machines and designs throughout the years, there has never been one that has stood out as perfect.
And as you may have guessed, vacuum technology has found its way into the consumers’ hands, providing a unique and delicious way to brew coffee. There is a lesser-known intricate brewing process called “Siphon” or “Vacuum Brewing”. A siphon coffee maker essentially brews coffee using vapor pressure to force boiling water upwards (from the bottom chamber to the top) to mix with the coffee grounds that sit in the upper chamber. The result is that it removes both oxygen and the carbon dioxide released from ground coffee as it mixes with hot water.
A siphon coffee maker contains two sections: a top container filled with fresh coffee grounds and a bottom container filled with water. By heating the water container, vapor pressure forces the water to rise into the top container where it is mixed with the coffee grounds. Then the heat is turned off. The resulting loss of vapor pressure will cause the water to drop back into the lower container through a cloth filter, leaving the spent coffee grounds above. And there you go, the perfectly brewed siphon coffee awaits in the bottom container.
This kind of process used to only be seen at well-known coffee shops, but now your average joe can whip up their own vacuum-inspired coffee, as there are several brands that can be purchased for your home.
If you were to think about the coffee industry, you probably wouldn’t consider how a simple vacuum has changed the way coffee is being produced, packaged, and brewed today. As technology continues to advance, so do creative engineers looking to find a more efficient way to do things. Coffee producers are constantly searching for ways to become more efficient, and vacuum presents an opportunity to do exactly that.
Are you in need of a Vacuum Pump? You can get the best from A-VAC. We are proud of our over 50-year history of providing economical high-quality Vacuum Pumps. Contact us for more information. And thank you for being an A-VAC customer!!