Lesson 7 - Hop Products SAQ

**You meet a brewer who is wanting to brew an unfiltered, high strength (7% abv) aromatic India Pale Ale (IPA) beer with a bitterness of 80 BU. The brewer has told you that they want to only use post-fermentation bittering as the hop utilisation can be over 90%; so it will be a great way to achieve the bitterness using fewer hops. Can you identify any potential issues they may have in achieving this beer using only post-fermentation bittering? Would you suggest any additional hop products (assuming the use of no other hop products for bittering)?

Response:

Since post-fermentation bittering tends to be via a purified iso-a-acid product, it contains no essential oils, β-acids or waxes. With no hops being added during wort boiling, especially at the high gravity required to achieve the alcohol, it is likely that there will be excess foaming or over boiling. This will result in wort losses. Although the beer will have a high abv, which will provide some protection against microbial infection, this protection will manifest itself late in fermentation. The wort and early stages of fermentation may be susceptible to bacterial infection without any iso-a-acid in the wort/beer.

The brewer would like an aromatic IPA, but Post Fermentation Bittering (PFB) products have no essential oils, so there will be no hop aroma if these are the only hop product used. This is the major issue with the planned scenario.

The lack of polyphenol and other hop material may negatively affect the mouthfeel of the beer.

Additional hop products would be:

• β-acids for antimicrobial activity.
• Hop waxes as an anti-foam.
• Hop oil products to achieve the desired aroma profile.
• Potentially a polyphenol extract to provide better mouthfeel. It can also increase the perceived sensorial bitterness, thus potentially reducing the amount of PFB product required.