Unlocking Coffee Aroma: Pre-Brew Systems Explained

The Intelligent Pre-Brew Aroma System (IPBAS) is a pre-brewing process that increases the contact time between water and coffee powder, allowing the maximum aroma to develop from coffee of any blend or roast. This process involves heating a small amount of filtered water, which is then fed into the brewing unit to wet the freshly ground coffee. The ground coffee swells, allowing aroma compounds to develop, which are then transferred into your cup during the Pulse Extraction Process (PEP). The Intelligent Pre-Brew Aroma System adjusts the amount of water based on the amount of coffee selected, ensuring an unrivaled flavour experience.

Coffee beans and carbon dioxide

The Intelligent Pre-Brew Aroma System (IPBAS) is a system designed to enhance the aroma of coffee beans before brewing. One of the critical aspects of achieving optimal coffee flavour is understanding the chemical changes that occur during and after the roasting process.

When coffee beans are roasted, gases, primarily carbon dioxide, form inside the beans. After roasting, the carbon dioxide starts to escape. During the first four hours post-roasting, a significant amount of carbon dioxide is released, and this process continues for up to two weeks. The rate of carbon dioxide release is influenced by the type of coffee and the roast. For example, darker and longer roasts tend to degas faster than lighter and shorter roasts.

To ensure the best flavour, it is essential to allow the beans to degas before brewing. If coffee is brewed too soon after roasting, the rapid escape of carbon dioxide during the brewing process will result in an uneven extraction, negatively impacting the taste. Therefore, coffee roasters typically wait a few days to a week after roasting before selling their coffee.

Additionally, grinding the beans accelerates the release of carbon dioxide. The finer the grind, the more cells that store gases are broken up and released. This is why it is recommended to grind coffee beans shortly before brewing. Allowing the grounds to bloom by adding a small amount of water and letting them sit for 30 to 40 seconds helps enhance the flavour. The blooming process releases carbon dioxide, which has a sour taste and interferes with the extraction of aromatics and oils by repelling water.

The role of water

Water is an essential component in the pre-brew aroma system, as it forms the majority of the final product, typically accounting for around 90-95% of the beer. The characteristics of the water used can significantly impact the brewing process and the final beverage. Here is a detailed look at the role of water in the pre-brew aroma system:

Solvent and Extractor:

Water acts as a solvent, extracting flavours and aromas from the malt and hops. It helps release aromatic compounds, contributing to the flavour profile of the beer. Water temperature plays a crucial role in this process, with the right temperature facilitating the extraction of desired flavours and aromas.

Medium for Starch Conversion:

During mashing, malted grains are mixed with hot water to convert starches into sugars through enzymatic breakdown. Water serves as a medium for this process, allowing enzymes to efficiently convert complex carbohydrates into simple sugars. The temperature and pH of the water are critical for activating these enzymes and optimising the mashing process.

Influence on Flavour and Aroma:

The mineral composition of water, including calcium, magnesium, and sulfates, impacts the flavour, aroma, and overall character of the beer. Different mineral levels can enhance or suppress certain flavours and aromas. For example, water with high sulfate levels may enhance hop bitterness, contributing to the desired hoppy and bitter flavour in some beer styles.

PH Adjustment:

The pH level of the water used in brewing affects enzymatic activity during mashing. Maintaining the correct pH range, typically between 2 and 5, ensures efficient enzymatic activity and maximises sugar extraction. Brewers often adjust the pH by adding brewing salts or acidifying agents to achieve the desired range.

Water Quality:

Water quality is critical in brewing, as it directly affects the taste, aroma, and overall quality of the beer. Undesirable compounds in water, such as chlorine or chloramines, can lead to off-flavors and impact yeast health during fermentation. Removing these compounds through water treatment, such as carbon filtration or chemical neutralisation, is essential for achieving consistent and high-quality beer.

In summary, the role of water in the pre-brew aroma system is multifaceted and complex. Water not only acts as a medium for extraction and enzymatic reactions but also influences the sensory characteristics of the final product. Brewers must carefully consider water composition, pH levels, and water treatment to optimise the brewing process and create beers with desirable attributes.

The Pulse Extraction Process

The E8 machine, for example, can produce a 2-ounce double espresso with an extraction time of around 24 seconds. This precise timing is challenging to achieve with other machines. The pulsing action of the P.E.P. system allows for better flavour extraction by exposing more surface area of the coffee grounds to the water.

The Z6 machine also utilises the P.E.P. system during the brewing cycle for espresso and specialty coffees. This feature strengthens the flavour and intensity of the coffee, addressing the common issue of sacrificing quality for convenience in superautomatic machines. The Z6's P.E.P. system, combined with Jura's preprogrammed dosage, enhances the strength and flavour of the coffee.

In addition to the P.E.P. technology, the Jura machines offer customisation options such as adjustable bean strength and grind settings, allowing users to fine-tune their coffee experience. The machines also have pre-infusion features, where the coffee grounds are briefly wetted before pressure is applied, further improving flavour extraction.

Coffee blends and roasting

Coffee blending is a well-regarded combination of sensory arts and practical considerations. It is a way to distinguish a coffee and is a staple on most coffee shop menus. Blends are defined as a mix of multiple lots, usually created by a roaster after sourcing.

Creating a coffee blend can be challenging, from knowing which coffees to mix to roasting beans of different origins, varieties, and densities. One of the main attributes of blends is "balance", where the flavours work harmoniously together. A common recipe includes a base, mid, and high note, which can be adjusted to create a clean and interesting cup of coffee with a steady flavour profile.

When creating a coffee blend, one must consider whether to blend the coffees before or after roasting. Pre-roast blending is easier for production as the roasting machine will homogenize the beans. It also requires less equipment and labour. However, it can be difficult for R&D as the team must taste, adjust, roast again, and wait for sufficient resting time. It is also challenging if the physical metrics of the green beans are very different, which can result in uneven coloration.

On the other hand, post-roast blending offers more flexibility for the R&D team as they can blend the roasted products on the spot for new iterations. While roasting independently can reduce challenges, the final blend may still contain variations in extraction due to the multiple roasts involved. Post-roast blends also take longer, require more labour and equipment, and can be less consistent in batch size.

The number of coffees in a blend and the minimum percentages of each are also important considerations. Most professionals recommend two to four parts, keeping things simple for development and production and allowing for easy identification of flavour profiles. Each component should ideally make up at least 8% of the final product to have a noticeable impact on the flavour.

Creating a signature blend can be a great opportunity for a roaster to improve their skills and create a brand-defining coffee that is in demand all year round. It takes time, practice, and creativity to master the skill of blending.

The brewing unit

The Pulse Extraction Process (P.E.P) then takes these aroma compounds from the ground coffee in the brewing unit and transfers them to your cup, resulting in a coffee with an unrivalled flavour and aroma. The Intelligent Pre-Brew Aroma System ensures that the amount of water is always adjusted according to the amount of coffee selected.

Frequently asked questions