Lesson 7 - Hop Products SAQ

*Indicate whether the following statements are true or false. Provide a reason if they are false.

a) Rho Iso-extract is the least bitter and Hexahydro Iso-extract is the most bitter.

b) Tetrahydro Iso-extract provides the most beer foam enhancing ability of the reduced hop extracts.

c) The combination of α-acids, UV light, a sulphur containing compound and riboflavin can cause the ‘off-flavour’ known as 3-methyl-2-butene-1-thiol.

d) The main advantage of hop oil products is their ability to standardise the hop aroma from brew to brew.

e) Only the α-acids and essential oils from the hops are beneficial in the production of hop products.

Response:

a) False. Tetrahydro Iso-extract is the most bitter, with a relative bittering of 160-180% compared to Iso-α-acids, followed by Hexahydro Iso-extract (100-120%) and then Rho Iso-extract (60-80%).

b) True. The reduced hops become more hydrophobic as the level of hydrogenation increases. Tetrahydro iso-extract has the highest level of hydrogenation of the Iso-extracts.

c) False. It is not the α-acids, but the iso-α-acids that are intrinsic to the reaction.

d) True. Whole hops and hop pellets (unless blended to achieve a standard) will have a natural variation in oil content depending on: where they are grown, variety, year they were grown, when they were harvested etc. Thus there may be differences in aroma if the amount of hops added to a brew remains the same.

e) False. β-acids are used to make anti-microbial hop products and the waxes/lipids can be extracted to make anti-foam products.