Beer, wine & cider Flashcards
_________ + ________ + __________ + ________ = BEER
water + malt + hops + yeast
What is beer:
Is a solution of water, alcohol and carbon dioxide that is flavored by carbohydrates, proteins, minerals, and different aromatic compounds that it acquires from malt, hops, and yeast.
Define gravity:
density of the wort, or a way of calculating the amount of dissolved substances, largely sugars that will be converted into alcohol (it is your first look at how alcoholic your final brew will be)
Gravity is expressed in ____________
Original Gravity (OG)
Original Gravity is expressed as a ___________________
ratio of density relative to pure water.
Gravity is normally calculated using either a ________ or a _________
hydrometer or refractometer
What is a hydrometer:
A weighted glass tube with a scale on the inside which stops at the relative density of the liquid being measured
What does a refractometer measure?
Measures the original gravity only, based on the refractive properties of sugar. Alcohol distorts the readings
What is the formulate for Alcohol by Volume (ABV)?
ABV = (OG-TG) * 131.25
What is terminal gravity?
is how much gravity is left after the fermentation is finished and can be used to calculate the alcohol content of the finished beer (or wine, or cider)
Define ABV in words:
The percentage of ethanol in the finished beer
What is used to assess colour of alcoholic beverages?
Tristimulus
Bitterness:
Is the level of bitterness you taste when you drink beer. It is measured in bitterness units (BU) which relates to ppm isomerized alpha acid
Apparent attenuation formula:
(OG-TG)/OG
Attenuation is a way to measure what…..
how complete a fermentation process is.
High apparent attenuation signifies a ________, while low apparent attenuation signify a sweet beer.
dry beer
sweet beer
Malting is :
the process of allowing the grain to germinate (usually by soaking them in water)
The aim of malting is to ____________________
to transform the food reserves in the grain into substrates that are convenient for fermenting in the brewery
The moisture content of the grains at the start and during storage should be no higher than ____
20%
The water is not left on the grains there are intermittent periods of _______ when air is blown though
drainage
Milling is process that does what ? _____________
It breaks down the malt into smaller more fermentable sizes
What are the 2 types of mill?
Wet milling and dry milling
After milling the malt grist is classified via a ______
sieve analysis
Mashing is the process where_____________________
ground malt is mixed with brewing water, such that a fermentable extract is produced that will support the growth of yeast
Mashing takes about ___ hours
3
After mashing ______ is produced
wort
What are the 3 varieties of hops?
- aroma hops
- alpha hops
- dual purpose hops
wort is boiled with hops for a bit over an hour before being cooled down and ____________ is added to start the fermentation
yeast
Sc is added to the wort in a very specific amount, adding too little leads to __________________, adding to much leads to _______________________
- very slow initial fermentations
- competition between yeast and poorer growth
TRUE OR FALSE : yeast stress can lead to undesirable fusel alcohol production
TRUE
What are fusel alcohols?
Alcohols that contain more than 2 carbons
_____________ conditions are essential for the production of alcohol by yeast, sugar up-take is diminished in the presence of oxygen
Anaerobic
During exponential growth yeast are at their highest level of utilizing ________ and producing ________________
sugars
ethanol and carbon dioxide
What are the 5 considerations during conditioning of beer :
1) Flavour maturation
2) Clarification
3) Stabilization
4) Carbonation
5) Minimize oxygen
Wine is an _____________________
alcoholic beverage made from grapes fermented without the addition of sugars, acids, enzymes, water, or other nutrients
_____________ must be added to most fruit wines
cane sugar
Superior wines cannot _______________
be blended with other wines
What are the steps in the wine making process?
1) sampling
2) harvest
3) crushing/pressing
4) fermentation
5) blending
6) stabilizing
7) aging
8) filtration
9) bottling
10) consumption
Wine fermentation typically comprises a _____________ which lasts a few hours, a short _________ (24-36 hr), and a long _______ during which most of the sugar is converted into alcohol
lag phase
growth phase
stationary phase
What happens to the yeast activity during the stationary phase?
the yeast activity continually decreases, although viability remains around 90% until the sugar is depleted
______________ is also important in the taste development of wine (what kind of fermentation)
Malolactic fermentation
What happens during malolactic fermentation?
During this process L-malic acid is converted into L-lactic acid and CO2
____________ is added to kill natural species and allow wine specific Sc (which are resistant to sulfur dioxide) to carry out the fermentation, but despite the addition of sulfur dioxide several different species of yeast participate in the process
Sulfur dioxide
Sulfur dioxide is widely used its ________________ and _____________ properties
antioxidative and antimicrobial
How does SO2 inhibit the growth of microbes?
by disrupting disulfide bonds in proteins and reactions with cofactors. It can also deaminate cytosine to uracil which increases the likelihood of fatal mutations
Cider is particularly prone to contamination with _________ so it is important to add sulfur dioxide at the initial fermentation step
acetic acid bacteria
Campden tablets are used to (name 3) __________________
- sterilize wine, cider and beer
- can also eliminate free chlorine from water solutions (i.e. if you use water from a municipal source)
- Are also used as an antioxidizing agent when transferring wine between containers. The sodium metabisulfite in the Campden tablets traps the oxygen that enters the wine, and prevent it from doing any harm
Campden tablets allows _____________
the easy measurements of very small quantities of sodium metabisulfite
What is a stuck fermentation?
which is when there is a premature cessation of alcohol production in the fermentation
A stuck fermentation can be caused by any of the following:
- Nutrient deficiency (nitrogen, vitamins, or minerals)
- Inhibitory Substances (acetic acid, lactic acid, excessive sulfur dioxide)
- Killer toxins (toxins produced by yeasts against other yeasts)
- pH too low (<3)
- Pesticides remain on grapes from field
- Temperature (too low at the beginning, or too high during the ferment)
Explain the relationship between LAB and wine
The growth of some LAB in wine produces desirable traits (malolactic fermentation), while the growth of some species just causes spoilage.
The growth of some LAB in wine produces desirable traits (malolactic fermentation), while the growth of some species just causes spoilage.
