3.2: Port - Winemaking Flashcards
How is fermentation stopped in Port production?
by the addition of grape spirit to create a sweet wine
How sweet are Ports usually?
usually 80-120 g/L residual sugar
Why do the extraction techniques have to be very effective?
maceration with the skins lasts for a maximum of two days
What are the 5 key methods of extraction during the fermentation?
- Foot treading in lagares
- Modern lagares
- Pumping over
- Stainless-steel pistons
- Autovinifiers
What are lagares? How were they traditionally made and used?
- singular lagar
- shallow (around 80 cm deep) square tanks, allowing a large surface area between the must and grape skins
- traditionally made from granite
- extraction would come from foot treading
Describe foot treading in lagares as an extraction method. Who uses this method?
- effective at extracting
- gentle enough not to crush the seeds (release bitter tannins)
- method used for a small number of premium and super-premium Ports
What is another name for modern lagares?
robotic lagares
Describe modern lagares.
silicon ‘feet’, attached to a stainless-steel gantry, press the grapes against the lagar floor and subsequently punch down the cap
What is the advantage of modern lagares?
- reduce the need for a large hired workforce, which can be difficult to obtain and unreliable
- can produce wines of equal quality to those that are produced by foot treading (but some producers continue to use foot treading for their most expensive wines)
What is the disadvantage of modern lagares?
initial investment for this equipment is higher
What is pumping over? Is it more or less effective than foot treading or modern lagares?
- same technique used for non-fortified wines
- can produce Ports with deep colour and high levels of concentration through frequent pumping over
- not as effective at extracting as foot treading or modern lagares
Describe the stainless-steel pistons method of extraction.
- uses open stainless-steel vats with pistons that punch down the cap to a programmed schedule
- can be used in conjunction with pumping over, which is usually needed to promote a more-even extraction
How effective is the stainless-steel pistons method of extraction?
- believed to be almost as effective at extracting as lagares
- seems to produce wines that are very similar in quality to those that have been made by foot treading in lagares
Describe how an autovinifier extracts.
- sealed concrete or stainless-steel tanks provide a solution to cap management that does not require electricity
- rising pressure of the CO2 produced from the fermentation pushes the juice up through pipes into a holding tank
- when CO2 pressure reaches certain level, valve automatically released
- wine in the holding tank, no longer supported by the gas pressure, sprays over the cap
What is a key advantage of the autovinifier method?
does not require electricity and therefore can be one of the cheapest options
What is a key disadvantage of the autovinifier method? For this reason, for what wines is this technique suitable?
- process is reliant on CO2 released from fermentation, very little extraction occurs before the fermentation starts
- means that the wines that this technique tends to produce are lighter in colour, body and flavour, suitable for basic Tawny, White and Ruby Ports
What is the most popular modern fermentation vessel? Why?
- stainless-steel
- easy temperature control (if necessary, the tank can be cooled to slow the fermentation and therefore prolong the period of extraction)
- easy to clean
In addition to stainless steel, what other vessels might a producer use for fermentation? For what types of wines might these vessels be more common?
- some producers use granite, concrete or old wooden vessels
- usually for small-volume wines
Are the grapes typically destemmed or not?
may or may not be destemmed
Why might a producer choose to destem?
unripe stems can impart bitterness
Why might a producer choose not to destem?
if stems are fully ripe they can aid pressing (reducing pressure of the pomace and enabling better drainage) after the fermentation has been stopped and free-run wine drained
At what temperature is the fermentation for red wines carried out? Why?
- 28-32°C
- warm enough to allow sufficient extraction
- not so warm that the fermentation progresses too quickly and reduces the available extraction time before pressing and fortification
At what temperature is the fermentation for white wines carried out?
- 20°C and below