CH 15 : Finishing and Packaging

Question 1

describe sedimentation?

Answer 1

clarifying the wine by allowing particles to settle and racking the wine off this sediment. Takes time so often used for premium/super premium wines

Question 2

What is centrifugation?

Answer 2

a clarification technique that uses centrifugal force to separate liquids and solids. It can replace depth filtration and hasten bottling. Primarily used in high-volume wineries.

Question 3

What is fining?

Answer 3

the removal on unstable colloids in the wine to clarify and stabilised it against hazes forming

Question 4

what is over-fining?

Answer 4

the desirable compounds are removed from the wine due to too much fining agents being added.

Question 5

how do fining agents work against colloids?

Answer 5

the agent has the opposite charge to the colloid and binds with it forming a filterable solid.

Question 6

What are the three kinds of fining agents

Answer 6

• removal of unstable proteins
• removal of phenolics that add unwanted colour and bitterness
• removal of colour and off odoursw

Question 7

what is an example of a fining agents that removes unstable proteins?

Answer 7

bentonite clay

can lead to colour loss in red and significant sediment means some wine is lost

Question 8

what fining agents remove undesirable phenolics

Answer 8

egg white
gelatine
casein
isinglass
vegetable protein products
PVPP

Question 9

describe filtration

Answer 9

the removal of unwanted solids from a wine through a physical barrier that traps these particles

Question 10

describe depth filtration

Answer 10

wine passes through different layers of a filter, catching different sized particles on the way.

can cope with many different particle sizes. Does not block easily. Too much pressure can push sediment through.

Question 11

what is sheet filtration?

Answer 11

pannels or sheet are stacked and the wine passes through, with sheets catching particles on the way. Costs to operate are low but the upfront cost is high.

Question 11

Describe how diatomaceous earth filtering works

Answer 11

DE is a form of depth filtration. The wet earth is used as a filter medium, as wine inside a rotary drum is sucked through it. Used to filter very cloudy wines.

Can expose the wine to oxygen. enclosed filters flushed with innert gas fix this problem

Question 12

what is surface filtration?two kinds of surface filtration systems?

Answer 12

membrane filters
cross flow filters

Question 13

what is stabilisation?

Answer 13

several winemaking interventions which mitigate unwanted effects in the finished wine post-bottling

Question 14

how would a winemaker ensure protein stability?

Answer 14

fining with bentonite

Question 15

what are the methods for creating tartrate stability in the wine?

Answer 15

cold stabilisation
contact ppress
electrodialysis
ion exchange
CMC
metatartaric acid

Question 16

what temperatures are required for cold stabilisation?

Answer 16

-4C for 8 days

Question 17

why would a winemaker use contact press over cold stabilisation for tartaric stability?

Answer 17

contact pressing is quicker, continuous, and more reliable than cold stabilisation.

It uses potassium bitartrate to speed up the crystallisation process. Takes 1-2 hours to form cristals that are filterable

Question 18

what tartaric stabilisation techniques would an early drinking wine employ?

Answer 18

metatartaric acid
`

Question 19

what is a good tartaric stabilisation method for cheap white wine?

Answer 19

CMC

Question 20

what is electrodialysis?

Answer 20

a charged membrane removes select ions to prevent the formation of tartrate cristals

Question 21

how does ion exchange work?

Answer 21

it develops tartaric stability by replacing potassium and calcium ions with hydrogen or sodium ions which will not drop out of solution

Question 22

how would a winemaker mitigate the risk of a secondary bottle ferment in sweet wines?

Answer 22

removing yeasts through sterile filtration

Question 23

what microbes can live in wines low pH and high alcohol levels?

Answer 23

lactic acid bacteria
brett
acetic acid bacteria

Question 24

how would a winemaker prevent Malo happening in-bottle?

Answer 24

ensuring it has already fully completed or filtering the wine to remove the bacteria

Question 25

how would a winemaker eliminate brettanomyces?

Answer 25

treatment with filtering or DMDC (dimethyl dicarbonate)

Question 26

what is measured in a chemical analysis?

Answer 26

alcohol
RS
free SO2
dissolved oxygen and CO2

Question 27

what are the broad amounts of free SO2 in white, red, and sweet wines?

Answer 27

white - 25-45 mg/L

red - 30-55 mg/L

sweet - 30-60 mg/L

Question 28

why will white wines require less free SO2 for stability?

Answer 28

because of the lower pH which promotes the efficacy of the free SO2w

Question 29

what is sparging?

Answer 29

the process of removing dissolved oxygen from wine using innert gas

Question 30

how will high levels of dissolved oxygen affect the wine?

Answer 30

it will accelerate the ageing process and reduce shelf life

Question 31

how would a winemaker fix cloudiness and hazes in the wine?

Answer 31

winery hygiene
chemical analysis and filtering
fining with bentonite

Question 32

what causes reduction?

Answer 32

yeast under stress due to low nitrogen levels or the absence of oxygen

Question 33

what is lightstrike?

Answer 33

caused by UV and certain wavelengths of visible light that reacts with the wine to form volatile sulphur compounds that give off an unpleasant smell

Question 34

how does one avoid brettanomyces?

Answer 34

good winery hygiene
SO2 level management
low pH
shortening vulnerable time between end of alcoholic conversion and start of MLC

Question 35

what are the ideal properties of a wine closure

Answer 35

-protects from rapid oxidation
-inert
- easy to remove and re-insert
- cheap, recyclable, fault-free

Question 36

what is HPLC and FTIR

Answer 36

high tech options for chemical analysis

High Performance Liquid Chromatography

Fourier Transform Infared Spectroscopy

Question 37

what is the OTR

Answer 37

oxygen transmission rate

Question 38

what is HACCP?

Answer 38

hazard Analysis of Critical Control Points

Question 39

What are ISO standards?

Answer 39

International Organisation for Standardisation