3.2 Winemaking Flashcards
In Port production, fermentation is stopped by…
In Port production, fermentation is stopped by…the addition of grape spirit to create a sweet wine (usually 80-120 g/L residual sugar).
The maceration with the skins lasts for a maximum of two days and therefore extraction techniques need to be very effective. List the key methods of extraction.
- Foot treading in lagares – Lagares (singular lagar) are shallow (around 80 cm deep) square tanks, allowing a large surface area between the must and grape skins. Traditionally, they were made from granite and the extraction would come from foot treading. Foot treading is effective at extracting but at the same time gentle enough not to crush the seeds, which would release bitter tannins. This is still the method used for a small number of premium and super-premium Ports.
- Modern lagares – Also called robotic lagares. More recently, modern lagares have been created in which silicon ‘feet’, attached to a stainless-steel gantry, press the grapes against the lagar floor and subsequently punch down the cap. The advantage of modern lagares is that they reduce the need for a large hired workforce, which can be difficult to obtain and unreliable, and however the initial investment for this equipment is higher. Modern lagares can produce wines of equal quality to those that are produced by foot treading, although some producers continue to use foot treading for their most expensive wines.
- Pumping over – This technique is the same as that used for non-fortified wines. Although this technique can produce Ports with deep colour and high levels of concentration through frequent pumping over, it is not as effective at extracting as foot treading or modern lagares.
- Stainless-steel pistons – This technique uses open stainless-steel vats with pistons that punch down the cap to a programmed schedule. This can be used in conjunction with pumping over, which is usually needed to promote a more-even extraction. This technique is believed to be almost as effective at extracting as lagares and seems to produce wines that are very similar in quality to those that have been made by foot treading in lagares.
- Autovinifiers – These sealed concrete or stainless-steel tanks provide a solution to cap management that does not require electricity. The rising pressure of the CO2 produced from the fermentation pushes the juice up through pipes into a holding tank. When the pressure of the CO2 reaches a certain level, a valve is automatically released and the wine in the holding tank, no longer supported by the gas pressure, sprays over the cap. The key advantage of this technique is that it does not require electricity and therefore can be one of the cheapest options. However, because the process is reliant on CO2 released from fermentation, very little extraction occurs before the fermentation starts. This 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.
Modern fermentation vessels (including those used in modern lagares) for Port production tend to be made from _____________.
Modern fermentation vessels (including those used in modern lagares) for Port production tend to be made from stainless steel.
This allows for easy temperature control and means that if necessary, the tank can be cooled to slow the fermentation and therefore prolong the period of extraction. Stainless steel also has the advantage of being easy to clean. Some producers use granite, concrete or old wooden vessels, usually for small-volume wines.
Are grapes destemmed in Port production?
The grapes may or may not be destemmed. Unripe stems can impart bitterness, however, if stems are fully ripe they can aid pressing (reducing compaction of the pomace and enabling better drainage) after the fermentation has been stopped and free-run wine drained.
Describe the fermentation process for Port.
Fermentation temperatures for red wines tend to be 28-32°C, warm enough to allow sufficient extraction but not so warm that the fermentation progresses too quickly and reduces the available extraction time before pressing and fortification. Fermentation temperatures for whites are around 20°C and below.
Many producers use ambient yeasts for fermentation as these are sufficient to start the ferment (and completing fermentation to dryness is not a concern for Port production).
What is the spirit used to fortify Port?
Typically, Aguardente.
Port legislation states that the spirit used to fortify the wine must come from grapes or other grape-derived products and it must be of ___% abv (+/- 0.5%).
Port legislation states that the spirit used to fortify the wine must come from grapes or other grape-derived products and it must be of 77% abv (+/- 0.5%).
All Port is fortified to an alcoholic strength between 19-22% abv. The alcoholic strength of the aguardente is relatively low compared to the 95-96% abv spirits used in many other fortified wines. Whereas 95-96% abv spirit is neutral, 77% abv has more character, and is the reason Port displays spirity aromas. Also, because of its relatively low alcoholic strength, a significant amount of spirit (approximately 1 L of spirit for every 4 L of fermenting must) needs to be added to produce a fortified wine of 20% abv, and therefore it is not surprising that the style and quality of the fortifying spirit has a significant influence on the style and quality of the wine.
From 1967 to 1976, all producers had to buy their aguardente from the ________________.
From 1967 to 1976, all producers had to buy their aguardente from the Casa do Douro.
From 1976, the IVP tendered the contract for the spirit. The aguardente was the same for all producers, and it was not of particularly high quality (cheap alcohol from southern Portugal, and then France). However, since 1991 producers have been able to source and buy their own aguardente.
Since 1991 when producers have been able to purchase their own aguardente, Port producers have gained a bettwe understanding of the role of spirits and may use slightly different ones in diferent wines. Why would they use anything different from aguardente?
Although all spirit must be 77% abv, some producers will use relatively neutral spirits to best show the character of the wine, whereas others will use spirits that are more aromatic (have more fruity esters) to add a certain character to their Port. The spirit chosen will also have an influence on the price of the final wine, therefore, high quality spirit will be added to premium wines, whereas less expensive spirit will be used in inexpensive wines.
Describe Port’s fermentation process.
The fermentation is stopped when the wine reaches around 5-7% abv and depends on the concentration of sugar the producer wants to retain in the final wine, generally 80-120 g/L. This can be a function of ‘house style’. The wine is drained from the skins before the aguardente is added. This means that draining must be as efficient as possible, as the must will continue fermenting during this time (until the fortifying alcohol is added), using up sugar that may be desired in the final wine.
Modern fermentation vessels (including modern lagares) are generally designed to drain as quickly as possible, compared to traditional granite lagares, which can take hours to drain.
True or false?
In Port, the mass of grape skins left after draining will be pressed and much of this press wine will be blended into the fortified free run wine to provide greater colour and tannin, necessary for wines that are to undergo long periods of ageing.
True.
True or false?
The grapes for Port are picked when the flavours and tannins are not ripe.
False.
The grapes for Port are picked when the flavours and tannins are ripe.
Too much potential alcohol is not an issue for these wines, but acidity can be low and pH high, and therefore ____________ is common.
Too much potential alcohol is not an issue for these wines, but acidity can be low and pH high, and therefore acidification is common.
True or false?
Ports do not go through malolactic conversion as lactic acid bacteria are unable to tolerate the high concentration of alcohol in the wine after fortification.
True.
All Ports spend their first winter in the ___________.
All Ports spend their first winter in the Douro.
During the months that follow fermentation the wines are left to clarify before they are racked off the gross lees. A rotary vacuum filter is often used to extract the remaining wine from the lees. In the spring, the wines may be shipped from wineries in the vineyard area to lodges in Vila Nova de Gaia.
