Maturation

Question 1

Maturation

Answer 1

The step or series of steps that convert green beer into finished beer.

Question 2

Warm maturation

Answer 2

Occurs immediately after fermentation, beer is held at similar temps to fermentation, allows flavours to stabalize

Question 3

Cold maturation

Answer 3

Occurs after warm maturation; primarily used to clarify and further mature the flavours in our beer and develop unwanted haziness.

beer is chilled and kept for -3 days “lagering” or “conditioning”

Question 4

Stabilising

Answer 4

Ensures the degree of haze remains constant

Question 5

Bottle & cask conditioning

Answer 5

When fermentation is close to completion, green beer is transferred to package, where maturation occurs. Naturally carbonated and clarified in packaging.

Question 6

Stokes law

Answer 6

Dictates the rate of settling increases when:
- particles are large and dense
- beer is stored in a shallow vessel rather than a deep one
- force of gravity is increased (e.g. in a centrifuge)
- the liquid is less dense

Question 7

Haze: solutions

Answer 7

Solids that have dissolved completely will appear clear, have no degraded or formed new compounds.

Question 8

Haze: Colloids

Answer 8

Solids too large to dissolve for a colloid; buoyancy causes them to remain suspended in the liquid eg. Milk, will appear opaque (non transparent)

Question 9

Haze: suspended solids

Answer 9

Initially opaque, but will settle out eventually e.g dirt in water. Particles exceed 1 micrometer and will not keep floating.

Question 10

Biological haze

Answer 10

Yeast, bacteria

Question 11

Non biological haze

Answer 11

Unfermentable sugars, B flu and (cell wall compounds), lipids, oxalates (salts from malts)

Question 12

Chill haze

Answer 12

Formed when polyphenols (malt during mash, hood during boil) and proteins (malt) interact

Question 13

How does chill haze become permanent haze?

Answer 13

Polyphenols become oxidised and interact with proteins and create a complex that Is to large to be soluble. Overtime, the complexes become larger and larger and become less soluble, even at warmer temps.

Question 14

Stabilising agents

Answer 14

Increase the clarity and shelf life of a beer; interacts with haze precursors to form large particles which are removed by filtration or sedimentation.

Question 15

Finings

Answer 15

Will remove haze from metal ion contamination, bacteria, non viable yeast, wild yeast. E.g. isinglass, gelatin

Question 16

PVPP Polyvinylpolypurrolidone

Answer 16

Synthetic nylon polymer that mimics a protein, removes polyphenols.

Question 17

Silica gel

Answer 17

Absorbs proteins by electrostatic attractions, absorbs proteins into pores within the structure of the silicate; removes proteins.

Question 18

Polysaccharide gums

Answer 18

Polysaccharide gums and plant extracts act similarly to collagen and gelatin. Interact with both proteins and yeast, forming complexes that precipitate.

Question 19

Tannic acid

Answer 19

Tannic acid is a polyphenol and binds to proteins to form permanent haze that can sediment out during cold maturation.

Question 20

Proteolytic enzymes

Answer 20

The plant - derived enzyme, papain, acts very differently to other stabilising agents. It is a proteolytic enzyme, isolated from the Papaya plant, which breaks down proteins into smaller segments. These smaller proteins do not form haze when they are hung to the polyphenols.

Question 21

Uni tank

Answer 21

Warm maturation can take place in the same fermentation vessel used for fermentation (often cylindroconical vessels, or CCVs)

Question 22

Horizontal cold maturation tanks

Answer 22

Typically chosen because they require less ceiling height

Question 23

Bottle and cask conditioning

Answer 23

Beer is removed from the fermenter and transferred to packaging: finings, additional sugar, addition yeast or hops are added and the bottle it cask is stored until the maturation process has completed.