Food gases are essential in the coffee industry. If, as we saw in a previous article, air is one of the main enemies of good espresso, CO2 and nitrogen are valuable allies throughout the production stages because they ensure a number of benefits. The first among them? They enhance the aromas. But that’s not all, the benefits affect many other aspects related to packaging coffee capsules with modified atmosphere (MAP).
In this we will illustrate the use of food gases, particularly the use of CO2 and nitrogen.
Food gases and coffee production: early stages
Before going into the details of capsule coffee packaging, particularly in modified atmosphere, and the benefits that food gases provide, a foreword.
In the coffee industry, attention is increasingly being paid to all those solutions that allow the preservation of the peculiarities of the bean throughout all stages of processing in order to ensure the highest quality of the final product.
Interest, however, is not limited to this: coffee roasters are looking for technologies that can increase productivity, optimize consumption and offer sustainability solutions to the end consumer as well, who is increasingly looking for environmentally friendly products.
Food gases and mixtures meet all these needs at the various stages.
1. Toasting and cryogenic cooling
When coffee undergoes roasting, new molecules are generated, by means of high-temperature degradation reactions, from those that originally characterize the coffee bean, which impart the typical aromatic and taste characteristics well known to us. To promote these hot reactions, without risking reaching a point where the bean is burned, it is advisable to contain the thermal inertia of the roasting process and cool the roasted product abruptly. Cryogenic liquids stop the reaction at the optimal time: this step, which is very delicate, if carried out with cryogenic techniques allows the organoleptic characteristics of the coffee not to be altered.
2. Toast grinding
Having completed the first stage, the wafer/capsule production chain makes it necessary to reduce the roast to powder by grinding under controlled conditions. In fact, during this process, close attention must be paid to flammability related to the presence of microparticles.
Coffee Cryomacination (or cryogenic grinding) helps to achieve both: liquid nitrogen reduces the average fineness of particles compared to noncryogenic grinding, resulting in a product capable of extracting more flavor with espresso machines, while allowing for a reduction in the heat generated and, by means of the inert atmosphere guaranteed in the grinding chamber, reducing the risk of flammability.
3. Storage
Reducing the percentage of oxygen inside the storage silos by adding nitrogen gas increases the maintenance of the organoleptic properties of the treated coffee.
4. Degassing
Alternating cycles of pressurizing storage silos with nitrogen gas and vacuum generated to remove the atmosphere in them removes the CO2 generated during roasting or released in the storage stages, thus enabling appropriate packaging operations. The use of gas in combination with vacuum allows the process, which is otherwise the “bottleneck” of the entire supply chain, to be speeded up.
Between roasting and grinding, decaffeination is possible: the CO2captures and stores the stimulant.
Once the coffee processing steps have been completed, the coffee is packaged, an activity that can be done by introducing the powder into dose capsules and pods, or into jars and bags.
5. Food gases and coffee capsule packaging
During the final packaging process of coffee, gases or gas mixtures can be employed in order to remove the natural residual moisture and oxygen in the product, which are responsible for bacterial growth or oxidation reactions, respectively.
Not only that, CO2 and nitrogen maintain the quality, aroma and taste of the final product, going so far as to enhance them.
Suffice it to give an example: the creaminess that characterizes some types of coffee is enhanced by the presence of CO2 in single-serve capsules. Food-grade carbon dioxide stabilizes the creamy layer created on the surface, increasing its intensity.
This explains, why, in coffee obtained by using mocha and vacuum-packed coffee, in a can or bag, the atmosphere is eliminated, lowering the risk of coffee degradation, but the same creaminess will not be obtained.
In summary, in capsules with MAP, whether in the flow pack (sealed sachet) or free, the food gas (in the first case present between the capsule and the packaging, in the second directly in the capsule) accentuates some qualitative characteristics and increases the shelf life of the product, with ecological benefits as well: the longer the shelf life, the less waste there will be.
The benefit is also productive, because the gases optimize processes, making them even faster. And again, with positive consequences for environmental sustainability as well, thanks to lower consumption.
Finally, the reasons that suggest the use of gas in the coffee industry are also structural and logistical: depending on how far the degassing process of the coffee is pushed, there is a tendency to progressively reduce the quantity of residual CO2 present inside it (and which will subsequently be released into the packaging). Generally, the more the degassing is pushed, the greater the ratio between nitrogen and CO2 used in the packaging mixture and vice versa, within certain proportions. In this way, the mixture manages both to stabilize the organoleptic properties of the coffee and to guarantee a structurally intact product after packaging. How? By avoiding, in the case of poor degassing, that the capsule swells excessively or, on the contrary, implodes.
