total resins 2

Question 1

What are the two main types of acids found in hops?

Answer 1

α-acids and β-acids

α-acids are isomerised during wort boiling, while β-acids are not.

Question 2

How do isohumulones and isocohumulones differ in terms of bitterness?

Answer 2

Isohumulones are more bitter than isocohumulones

This is based on their chemical properties.

Question 3

What happens to isohumulone levels during the brewing process?

Answer 3

They decrease due to adsorption to yeast cells and in foam

This affects the final bitterness of the beer.

Question 4

What is the solubility difference between isohumulone and isocohumulone?

Answer 4

Isocohumulone has higher solubility due to higher polarity

This affects the bitterness perception in beer.

Question 5

What percentage of β-acids added to the wort ends up in the trub?

Answer 5

Around 80%

Only about 20% are converted through wort boiling.

Question 6

What transformation occurs to β-acids during wort boiling?

Answer 6

They are converted into products formed from oxidation

These products also provide bitterness.

Question 7

What are hulupones and how do they relate to beer bitterness?

Answer 7

They are oxidation products of β-acids that may contribute to bitterness

They synergise with iso-α-acids for a smoother bitterness.

Question 8

What are humulinones?

Answer 8

Oxidised α-acids that are soluble in beer and contribute to bitterness

They are approximately 66% as bitter as iso-α-acids.

Question 9

What is the primary component of hard resins derived from hops?

Answer 9

Xanthohumol

It is a chalcone and has potential health benefits.

Question 10

What are some health problems that xanthohumol has been used to combat?

Answer 10

• Cancer
• Inflammation
• Viruses
• Bacteria
• Osteoarthritis
• Diabetes
• Atherosclerosis
• Cellular damage due to free radicals

However, its levels in beer are very low.

Question 11

What effect do hard resins have on beer’s quality?

Answer 11

They positively influence the bitter quality and foam stabilisation

They have an additive effect on iso-α-acids.

Question 12

Fill in the blank: β-acids are present in significantly lower quantities than _______.

Answer 12

α-acids

Question 13

True or False: β-acids undergo isomerisation during wort boiling.

Answer 13

False

Unlike α-acids, β-acids do not undergo isomerisation.

Question 14

What fraction of soft resins is of little interest to brewers?

Answer 14

Uncharacterised soft resins

They are not covered in detail.

Question 15

What is the main reason brewers are interested in the composition of α-acids?

Answer 15

They are isomerised into iso-α-acids, which provide bitterness

The composition affects the final bitterness of the beer.