De-stemming (Égrappage)
You can't say if it's common or not to let the stalks ferment together with the grapes in Chateauneuf du Pape. According to the old traditions there was no de-stemming but many producers do it today, some do it always, some do it never and some do it sometimes for some varieties and depending of the ripeness.
If de-stemming always is done the reason may be that you want to avoid every risk of adding an unpleasant taste to the wine from unripe stalks - herbaceous taste with a bitter undertone.
If de-stemming is never done the reason may be that you want to underline that the wines are made in the traditional way and the tannins from the stalks can certainly bring the expression of the single vintages.
The de-stemming equipment normally also crush the grapes in a gentle way giving the optimum conditions for the following fermentation.

Alcoholic fermentation and maceration
The alcoholic fermentation start quite quickly when the slightly crushed grapes are transferred to the fermentation tank. At first the natural yeast (Saccharomyces cerevisiae - see photo to the right) from the skin of the grapes multiply and then they begin consuming the sugar in the juice. The result of this process is that the sugar are converted into alcohol and carbon dioxide. The process will end when the sugar is consumed or the alcohol percent reaches a level that kills the rest of the yeast -  approximately 15 percent.
The fermentation process requires control of the temperature as the process itself increases the temperature in the must. White wines are fermented slowly with lower temperature but for red wines a higher temperature is wanted because this promotes the maceration. Normally the fermentation will last for 7 to 30 days. The maceration process will then also normally be finished but can be continued for some time after the end of the fermentation if wanted. The maceration is the process where extraction of the colour, the tannins and other wanted elements from the skin and perhaps from the stalks of the grapes takes place.

Trough the fermentation and maceration processes for the red wines the wine maker makes the first determinations about the character of the wine. He may want a straight forward wine meant to be drunk young or a more strong structured wine with more fruit, tannin and body meant to be kept in the cellar or in bottles for many years. The duration of the maceration period is important.

Remontage
During the fermentation and maceration a floating layer of grape skins will have a tendency to lie at the top of the most (the cap). Therefore it's necessary to reassemble the must and the cap. This is done by pumping the must over the cap or perhaps by manual or mechanical stirring.

Pressing
After the maceration the most is separated from the pulp and transferred to the vessels for maturation before bottling. Different presses can be used. The traditional vertical press of wood is still used also new ones (photo to the right) but now many use horizontal  presses of steel especially for the white wines.
Most of the wine (approximately 80%) runs freely from the tank (Vin de goute) then some more must comes from light pressing (Vin de press). The quality of the press wine decides if it is all blended again with the free run wine.

Malolactic fermentation
Shortly after the end of the primary (alcoholic) fermentation the second (malolactic) fermentation occurs automatically. In this process malic acid is converted into lactic acid undertaken by bacteria foremost Oenococcus oeni. The lactic acid tastes less sour and more friendly than the malic acid which can give the red wine a hard and metallic character.
For the white wines this process are usually stopped because the white wines from the warm area has a tendency to lack acid.
The malolactic fermentation can last for some time and is finished in the vessels for maturing the wine.

Maturing - ageing
Most of the white wines are matured in steel tanks and bottled less than a year after the harvest but some special cuvées are matured in wood and not bottled before one - two years after the harvest.
Traditionally the red wine is matured in foudres (big casks of wood) containing 30-60 hl. You can meet many different sizes of smaller casks or barrels in Chateauneuf du Pape: demi-muids (600l) or barriques (225-228l).
The ageing/maturing period (from harvest to bottling) for the red wines vary in Chateauneuf du Pape from one year to between two to three years. The period vary depending of the quality of the harvest.
For the normal red Chateauneuf du Pape (not special cuvées) the aging in wood is not done to extract tannins or taste from the wood but to let the wine oxidize slowly and in this way bring the wanted balance to the wine and when the producer finds this is achieved he bottles the wine.
Some producers don't use wood at all to mature the wine but only use  tanks of steel or cement. You have to be an experienced taster to  decide if wood have been used or not.
Some producers age in both tanks and wood.
Some producers mostly use foudres and perhaps smaller wood vessels for part of the wine (demi-muids or barriques)
Some producers have no or very few foudres and use only demi-muids or barriques.
When it comes to the special cuvées some producers use new or newer barriques but these wines are often produced in very tiny quantities can hardly be called typical wines from the appellation but they can obtain high scores from the wine tasters and high prices and in this way have some marketing effect for the producer..
Normally the red wines are bottled 18 - 24 months after the harvest.