Once again, welcome to our fascinating world of instant Coffees, if you recall our last article, soluble coffee started with David Strang of Invercargill, New Zealand in 1890 and it was just on 1960 that the freeze-drying process was introduced in the industry to improve the quality and flavor of instant coffee until our days that these processes have been improved to get the best out of each coffee bean. But let’s start from the beginning. Help me describe what you consider the start of a great morning? Nothing like a great cup of coffee, with a unique aroma and flavor to awaken you, to give you all the energy you need to start a perfect day. Isn't that true? Then , what do you consider a great coffee? I would say you can call it an enigma, because a great coffee is the coffee you like best, and each person likes the coffee in a different way, either bitter or sweet, strong or light, small or large, mixed with milk, or cocoa and milk, or with a hint of liquor… well that is the best coffee then, the one each person likes best.
Now, in my opinion, coffee has two main worlds, roasted and ground coffee world and instant coffee world and when we go into instant coffees there are two main different processes that define the coffee aromas and flavors. I would say that the big work here is how is this coffee going to be processed to convert into instant coffee (powder or small grains of instant coffee). In the instant coffees we have the spray drying and the freeze drying processes, both processes need the coffee beverage or soluble solids of coffee to start their processes, however in this middle part there are also a couple of different processes, you can either concentrate the liquid coffee by hot temperature by evaporating part of the water or by freeze concentration that you get part of the water out of the liquid coffee by freezing it and as the soluble solids of coffee have a lower freezing point than water, if they go down on temperature only to the freezing point of water that is zero celsius, they only freeze water and extracted from the soluble solids of coffee or liquid coffee. In these two ways of concentrating coffee the main difference is the temperature, if you submit a liquid to hot temperatures to evaporate it, the volatile part of the product will also evaporate, so many coffee aromas get lost in this evaporation process, however if we speak about economy, it is cheaper to evaporate than to freeze, so many soluble coffee industries use evaporation. Hah, but this does not stop here, if you evaporate aromas, what else can you do?
Well, in the coffee world there has been a lot of research too, and many improvements, so now they have industrial processes to capture the aromas that get lost from the coffee in different processes as in the evaporation and these captured aromas are then returned to the instant coffee at the final stages of their process, meaning when they have the instant coffee ready to pack, they can add again the coffee aromas captured in previous processes, however the coffee taste will keep having that burnt sweet characteristic of the classic instant coffees due to the evaporation process.
Then in these two processes (evaporation and freeze concentration) we will start to find differences in the final aroma and flavor of the coffee. If we submit a liquid coffee to high temperatures to evaporate water, we will burn it a bit and also caramelize the natural sugars present in the coffee beverage, there we will feel the difference in the cup when we taste it, and that's why some people might say that the instant coffee taste different, like sweeter and burned, but then again, as I said before, the best cup of coffee is the coffee you like best, there are many people around the world that prefer this sweet burnt flavor in their coffee cup.
Now continuing with the instant coffee processes, and after the liquid coffee has been concentrated by either of those two methods (evaporation and freeze concentration), in order to extract the final water out, there are two ways to do it, by the Spray drying or by freeze drying. Let's talk about spray drying, this is a well know process used in many industries, not only food industry but pharmaceutical, petroleum and chemical industries, in this process and talking specifically about coffee, the liquid concentrated coffee goes to a spraying tower by the upper part and it is sprayed with a nozzle that makes liquid particles really small like a mist while from the lower part of this tower hot dry air is forced in to dry those particles, condensed water is extracted from the upper part of the tower as the coffee dry powder goes down by gravity and it is collected on the lower part of the tower. So, finally talking about the final coffee powder obtained, this spray drying will enhance that burnt and sweeter flavor of the final instant coffee.
What is the goal for instant coffee? To be as close in aroma and flavor as possible to the fresh roasted and ground coffee, right? Well, the processes that preserve the most are the ones of lower temperatures, that is freeze concentration and freeze drying, as they do not alter as much the flavor and aroma of a fresh roasted and ground coffee.
As on my last article I explained in detail the freeze drying process, so I will not go into this process much in this article, however now that we have compared it other processes to obtain an instant coffee you know why the freeze drying process is a more delicate process with the product, it is also indeed the most expensive process but preserves the most of a roasted and ground coffee not only in flavor but in aromas.
Do not go far, in my next article I will be talking about additional improvements on the instant coffee world that will make your head spin
By Raul Valencia
