How To Freeze Dry Coffee At Home

How To Freeze Dry Coffee At Home

1. Grind the coffee beans to a medium-fine consistency
2. Place the ground coffee in a single layer on a tray or sheet pan, and freeze it for at least 12 hours or overnight
3. Place the frozen coffee in the freeze dryer and follow the manufacturer’s instructions
4. Allow the freeze-drying process to complete, which can take 24-48 hours depending on the size and moisture content of the coffee,

Even by freezing the grounds or coffee beans to prolong their shelf life, the instant coffee made from frozen-drying crystals still has longer shelf life. This is because the freezing-drying process produces ultra-dry coffee crystals, which are stored long-term.

Because no hot temperatures are used in the freeze-drying process, flavor compounds cannot escape from the coffee crystals. Using the process allows producers to vary the pressures and temperatures, dehydrating coffee below freezing temperatures, helping retain all of the flavors. At that stage, water from the extracted coffee is removed using a method such as spray drying or freezing, in order to grind it into a powder.

After steeping, water is removed from extracts through evaporation and frozen to produce dried beans or powder. After filtering out the coffee, a portion of the water is removed, either by evaporation or freezing, to boost concentration (a bit like concentrate in cold brew). What makes instant coffee is when all of the water is removed from the brewed product, leaving dehydrated coffee crystals.

There are two methods used to dehydrate the brewed coffee to create instant, so let us look at them in detail. The freeze-drying method is more involved, requiring the coffee to be cooked into extract, then chilled down to become the sorted extract slurry.

A spray-drying method occurs by spraying the liquid coffee concentrate out in warm air, creating a very fine mist. Spray drying is a process that turns the liquid coffee into a fine mist, and squirts it out into a tall, large chamber filled with rotating hot air, which can reach temperatures as high as 400-500 F. For various reasons, spray drying produces an instant coffee of better quality than other methods.

Despite being the most economical method for producing instant coffee, the tremendous aroma loss of the Spray Drying process results in a sub-par product. This is because frozen-dried instant coffee retains coffees appealing aromas and flavors, whereas most are lost during spray-drying. It is easy to see why major coffee companies favor dissolving rather than freezing, when it comes to their coffee beans.

The freeze-drying process is considered to have better quality when it comes to instant coffee, and so is still used today by Nestle for their Nestle Necafe Coffee. Freeze drying not only produces super-dry crystals, it also preserves the natural, tasty flavor of the brewed coffee, without any burning flavors. As a result, the fresh-roasted coffee is frozen at temperatures below freezing, while a freezing-drying machine creates a vacuum so that there is less pressure within the product.

To remove the water from frozen coffee, keeping temperatures below zero degrees, little heat is applied to the coffee. Once removal is completed, some heat is applied to the frozen coffee for any remaining water to sublimate. The grounds are then placed into the vacuum chamber for the final step, in which the remaining frozen water is heated and converted into vapor, leaving large, tiny pieces of coffee to be dropped into your cup.

It is mixed up until all of the grounds are dissolving, leaving you with some kind of super-concentrated coffee liquid in the bottom of the cup. Mixing coffee granules in cold water will first dissolve them slightly more gently, eliminating that powdery flavor.

When the coffee granules come out of a high-pressure vacuum, the granules are successfully dried, retaining their aromatics. Once dried coffee extract is converted to coffee granules, they stay solid at room temperature until poured over boiling water, at which point they dissolve.

Coffee beans are ground to a fine powder, mixed with water, and sprayed in the chamber in which coffee is heated. The extract is then further chilled down to about -40 degrees F, which results in the formation of Coffee Flour. The grounds are now mixed with water for the steep, just as one would at home using a French Press (cafetiere). The large machine makes coffee — and then it warms up the coffee, removing part of the water, turning the liquid into coffee extract.

The heat quickly evaporates water out of the dense concentrate, leaving the coffee falling on the floor in dry lumps. Next, the solid mass is placed into the drying chamber (vacuum chamber), typically a metal tray, and the chamber is converted to a vacuum with enough force to very rapidly dry the coffee. Once the coffee powder has been frozen, it is taken from the freezer into a drying chamber. Put the freezing bag back in a freezer and repeat this process every 24 hours until your coffee beans are fully frozen.

The longer coffee is exposed to its surroundings, the faster it loses its flavour (3), so any drying process needs to occur rapidly. The process of freezing, thawing, and re-freezing every time you pull the coffee to brew also produces unwanted humidity. Like ground coffee and coffee beans, excessive humidity negatively affects instant coffee, so you are better off without freezing. By using this kind of instant coffee, you get coffee without worrying about it going bad fast, and without all of the risks of freezing coffee.

Thanks to this hack on instant coffee, however, you can actually take those ugly little frozen-dry crystals of java and turn it into something worthy of a drink. In freezing-drying, the coffee grains are frozen extremely fast in order to prevent the creation of larger ice crystals, creating a porous quality, and unwanted colour changes. Essentially, ice moves straight from the frozen state to a gaseous state, skipping over the liquid stage completely, leaving behind just the dried coffee crystals as the byproduct of the process. Freezing to desiccate involves freezing a product, and then using a vacuum pump to remove the moisture from the frozen material.

How do I freeze dry coffee?

In order to obtain solid soluble coffee, it is necessary to dry the coffee extract after it has been filtered. A thin layer of the liquor is formed by freezing the contents to a shallow temperature (about -40°C) and breaking it into small pieces. To freeze-dry the frozen product, these granules are then loaded into the freeze-dryer, which can be used in batch or continuous mode.

Can you freeze-dry your coffee?

It is preferable to freeze your coffee rather than freeze it when it is freeze-dried. By freeze-drying coffee crystals, they become highly durable and can be stored for an extended period of time. The shelf life of this coffee is much longer than the shelf life of most other kinds of coffee.

Is freeze dried coffee the same as instant coffee?

Spray drying is a method to make instant coffee powder, while freeze-drying helps make instant coffee crystals. Because of the flavor preserving process, freeze-dried coffee has relatively high quality and better taste, whereas instant coffee powder tastes more burnt.