How Does a Particular Hop, or Malt, Contribute to the Final Aroma, Flavour, and Character of a Beer?

In craft brewing, malt provides the foundational body, sweetness, and colour, while hops contribute bitterness to balance the malt and add distinct aromas and flavours. The final character of a beer depends on the specific variety of each ingredient and how it is used during the brewing process. 

The Contribution of Malt

Malt is grain, most commonly barley, that has been steeped in water to germinate, and then dried in a kiln. This process releases enzymes that convert starches into fermentable sugars, which the yeast consumes. The degree of heating and roasting during the malting process determines the grain's flavour and colour. 

Common Malts and Their Flavour Profiles

• Pale Malt: As a base malt, it provides a clean, subtle sweetness and a pale colour. It forms the backbone for many beer styles, from pale ales to lagers.

• Vienna Malt and Munich Malt: Kilned at higher temperatures, these malts create a rich, malty flavour with notes of toast and biscuit. They also impart a beautiful golden or amber colour and are often used in Marzens and Bocks.

• Crystal/Caramel Malts: These are roasted in a special drum after being soaked, causing the starches to turn into sugar inside the grain. The resulting malts add caramel, toffee, and raisin flavours, as well as sweetness and a fuller body.

• Chocolate Malt: Despite the name, this malt does not contain chocolate. It is roasted at high temperatures to give beers a dark colour and roasted notes of coffee and dark chocolate.

• Black Malt and Roasted Barley: These are roasted even higher for intense, acrid flavours. They provide a dark, opaque colour and are key for stouts and porters.

• Adjuncts (Wheat, Oats, Rye): While not always malted, these grains affect the beer's body and texture. Oats, for instance, are used to create a rich, creamy mouthfeel, especially in hazy IPAs and stouts. 

The Contribution of Hops

Hops are the cone-shaped flowers of the Humulus lupulus plant. They contain alpha acids, which primarily contribute bitterness, and essential oils, which provide a wide range of flavours and aromas. 

The importance of Timing

The brewer's 'hop schedule' dictates how the final beer will taste. Adding hops at different stages of the boil produces different effects. 

• Bittering Hops: Added at the start of the boil and cooked for 60 minutes or more. The long, high-temperature boil isomerizes the alpha acids, creating the bitterness that balances the malt's sweetness.

• Flavour Hops: Added in the last 30 minutes of the boil. This shorter boil time extracts some bitterness while preserving more of the hop oils, which provide flavour.

• Aroma Hops: Added during the last few minutes of the boil or at 'flame out' to retain the volatile aromatic oils. These are responsible for the beer's fragrant bouquet.

• Dry Hopping: This process involves adding hops to the beer after fermentation is complete. Because it bypasses the boil entirely, it imparts maximum hop aroma without adding bitterness.

Common Hops and Their Flavour Profiles

• American Hops (e.g., Cascade, Citra, Mosaic): These often have bold, punchy characteristics and are popular in IPAs.

  • Cascade: Features distinct citrus (grapefruit) and floral notes.

  • Citra: Known for its strong citrus and tropical fruit aromas.

  • Mosaic: Provides a complex mix of earthy, piney, and fruity characteristics.

• Noble Hops (e.g., Saaz, Hallertau): Traditional European varieties with delicate, spicy, and earthy characteristics. They are the classic choice for pilsners and other lagers.

• English Hops (e.g., East Kent Goldings): These are known for their subtle, earthy, and herbal qualities. East Kent Goldings can also bring bright, peppery, or lemon-lime notes.

• New Zealand Hops (e.g., Nelson Sauvin): Often deliver vibrant, tropical fruit aromas, which can include gooseberry and white wine characteristics.