Preparing the food for freezing:
Dr. Monika Fekete discusses how to keep fresh coffee beans* and the importance of carefully packing them before freezing.
*In this case, fresh refers to freshly roasted coffee beans.
It’s lovely to see the streets of Melbourne come alive with people eating lunch. When cafes reopen around the country, bartenders and managers can reassess their supply of roasted coffee beans. Over the last few months, sales have fluctuated dramatically, with some coffees remaining on the shelves for longer than usual. Is it, however, still suitable for serving, and how can we keep coffee fresh for longer?
Let’s have a look at what happens to coffee once it’s been roasted. More than 800 chemicals are produced during the roasting of coffee, with over 300 of them being essential aromatic compounds. These molecules are imperative freshness markers; however, they are readily lost due to diffusion.
Physical changes within the bean and the profound shift in chemical composition hasten the process. During roasting, the concentration of heated gases breaks down intercellular barriers, resulting in increased porosity. Volatile materials and carbon dioxide (CO2) are absorbed inside the pores, contributing significantly to the coffee’s quality. However, because a more excellent surface is exposed to the medium surrounding the bean, higher porosity causes a rapid loss of volatile chemicals.
Index of Freshness coffee
Carbon dioxide: as the roasting temperature rises, the amount of CO2 produced and retained inside the porous structure of coffee beans rises. However, when the roasting temperature exceeds 220°C, the cell walls lose their flexibility, and fissures occur, allowing CO2 to escape more quickly.
Volatile flavors: Diffusion also loses flammable Maillard reaction products (MRP) along with CO2. Many studies have revealed that some crucial molecules like Methanethiol, which has a sulphury odor that we may find unpleasant but recognize as one of the essential indications of freshness in coffee, are to blame for much of the loss of scent. The fruity, malty, floral, honey, and buttery fragrances, all of which are intimately related to that exquisite, fresh coffee smell, are caused by Strecker-aldehyde and dicarbonyls.
Lipids: Lipids make up roughly 15% of the dry weight of roasted Arabica coffee. When coffee oils are exposed to air, they can oxidize and deteriorate, giving off the rancid odor we associate with bad coffee.
Storage environment coffee
The most straightforward approach to keep roasted coffee fresh longer is to keep it free from oxygen, which speeds up the biological reactions in various ways. Freshness flavorings are prone to oxidation and can be lost quickly after roasting, while lipid oxidation causes rancidity.
Sensory investigations have demonstrated that even a modest amount of oxygen significantly impacts the quality of coffee over time. Figure 1 depicts how oxygen has a significant impact on shelf life. In this case, when the oxygen concentration during storage climbed from 0.5 percent (low oxygen environment) to 21% (high oxygen environment), shelf life was reduced by around 20 times (in the air).
Another thing to keep in mind is that the shelf life is drastically reduced from 0% to 5% oxygen when the oxygen concentration increases from 0.1 to 1.1 percent, the shelf life in half. The rate of degradation increases by 10% for every 1% increase in oxygen content. While such low oxygen levels in packaging are difficult to obtain, it demonstrates how critical it is to keep coffee away from oxygen to maintain freshness.
Moisture is the second most serious hazard.
Roasted coffee is a dehydrated product with just about 0.75 percent moisture content on a dry basis. This renders the coffee microbiological and enzymatically resistant to deterioration. On the other hand, coffee can absorb moisture from the air hasten the loss of volatile chemicals. Due to hygroscopicity, the beans’ brittle and delicate structure progressively loses its characteristic crispness and crunch.
Even though the temperature is the most significant aspect to consider while storing coffee, it is the third most important environmental factor impacting coffee freshness. This indicates that after the oxygen and moisture barriers have been established by selecting appropriate packing, we should pay attention to the storage temperature.
The Arrhenius equation asserts that chemical reactions occur at a quicker rate at higher temperatures and can be used to explain the effect of temperature on the release of CO2 and volatiles.
Maria Cristina Nicoli’s coffee tests have demonstrated this. The degassing rate rose 1.5-fold for whole-grain coffee and three-fold for ground coffee for every ten °C rises (examined between 5°C and 45°C). These losses are the most significant during the first few days of coffee storage.
Because processes slow down at cooler temperatures, coffee has been refrigerated or frozen as a preservation method.
Light can speed up hunting by acting as a catalyst in several chemical reactions. Most methods of packaging, fortunately, shield the coffee from light exposure. The essential aspect we can control to extend shelf life is the packaging.
Let’s take a look at some of the most common coffee choices.
The most basic sort of coffee packaging is paper or plastic. It shields the coffee from light and moisture, but because it contains a lot of oxygen, the stalking processes might happen quickly. To avoid bursting bags due to ongoing CO2 leakage, this packaging style can only be used on coffee that has been degassed previously. This problem can be solved by installing a check valve. It helps to eliminate extra air, but CO2 tends to lie lower due to its more considerable molecular weight, whitening the beans. Some CO2 and volatiles will leak through, dulling the coffee’s flavor.
Vacuum packaging is an old and widely used method for packaging a wide range of foods. It helps avoid oxidation reactions that are harmful to the shelf life by lowering the amount of oxygen available inside the packaging. The vacuum efficiently suckers the scent out of the coffee: the volatiles leave as soon as the package is opened. This is its biggest downside.
Modified Atmospheric Packing (MAP) is a highly effective method of excluding oxygen from product packaging, significantly increasing shelf life. Major worldwide coffee firms are now using MAP to keep fresh coffee from being exported. Nitrogen flushing into coffee bags is becoming increasingly popular among small, specialist roasters, though the organoleptic outcomes are debatable.
The use of pressure packaging is a novel concept. It permits CO2 and volatiles to build up until pressure forces them back into the beans, where they dissolve in the coffee oil or bind with melanoidin. The tension spreads the oil inside the baffles, producing a second barrier to oxygen inside the bean. As a result, aging in a pressured vessel can help improve the cup’s quality. The disadvantage is the increased material cost.
Active packaging is a system in which the product, package, and environment all work together to extend the product’s shelf life. The oxygen absorber, primarily iron powder, is today’s most extensively used active encapsulation technology. The pros and disadvantages of each packaging style and the shelf life it may reach, are listed in Table 1.
Consider packaging alternatives first and storage temperature second to help coffee last longer. After choosing the type of packaging, the temperature will become the most critical factor impacting shelf life during storage. So, once you’ve sorted your bags, put them in the freezer.
Store ground coffee
It should come as no surprise that freshly ground coffee beans produce a better cup. On busy mornings, however, many of us are willing to skip the step of grinding beans. This is where pre-ground coffee comes into play.
This handy staple allows us to get our caffeine fix in a matter of minutes. And, when stored properly, it tastes almost as good as fresh. That’s why we researched the best ways to store ground coffee. We’ll discuss everything from storage locations to the best containers—and much more.
Store coffee beans
Air, moisture, heat, and light are your beans’ worst enemies.
To keep your beans’ fresh roasted flavor as long as possible, store them at room temperature in an opaque, airtight container. Green coffee beans can be lovely, but avoid clear canisters that allow light to interfere with the flavor of your coffee.
Keep your beans in a cool, dark place. A cabinet near the oven is frequently overheated, as is a spot on the kitchen counter that receives direct afternoon sunlight.
Coffee’s retail packaging is not usually suitable for long-term storage. Invest in airtight storage canisters if at all possible.
Is it true that fresh coffee tastes the best?
Both yes and no. Coffee typically reaches its peak flavor potential between 48 hours and 1 month after roasting.What makes a perfect cup?
Aroma, Acidity, Sweetness, Body, and Bitterness will be perfectly balanced in your Optimal Cup.
Essentially, the cup tastes the best!
While freshness is a good indicator of your cup’s potential aroma, there are many other factors to consider in order to achieve your ideal flavor experience