Where in the Catholic Church is red wine used for mass? In any Catholic Mass I attended (in Germany) white wine was used for the holy Eucharist. There are some plausible practical reasons for that. Are there regions of the world where mostly red wine is used?
Where in the Catholic Church is red wine used for mass?

In those areas in which the local community and/or parish priest's choice is to use red wine over white wine for Mass.

Where I live (British Columbia, Canada) red wine is quite popular. Some priests use white wine for Mass here, but most here use the red. A lot will depend on the availability of the Altar wine offered in  a particular area, as well to the personal choice or the priest saying Mass. I have never heard of any bishop insisting on a particular colour for his diocese. I have, one the other hand, known of some religious communities that grow their own grapes and will keep separate the coloured grapes for a particular usage. For example the red wine will be for table wine and the white wine will be for the altar wine or vise versa. I have seen this in French Benedictine communities.


  Regarding the Wine Used for Mass
  
  Red or White?
  
  Nothing is specified canonically as to whether the wine is to be a red, a white or a blush. This determination is left to the individual community. The general consensus, however, is that most people prefer a wine that is a bit sweet and fruity. What is indicated is that to be considered valid sacramental matter the wine is to be natural and made from grapes (cf. Canon 924 §3). Wine made from any fruit other than grapes is considered invalid matter.
  
  Alcohol Content
  
  A minimum or maximum level has never been specified in canonical literature since the revision of the Code of Canon Law in 1983; however, in the estimation of canonists, it usually falls somewhere below 20%. Generally speaking, the alcohol content for most commercially produced wines is between 8% and 17%.
  
  If mustum were to be used it cannot have an alcohol content of less than 1%. Mustum is grape juice in which the fermentation process has begun, but has been suspended. Mustum is reserved for those who suffer from alcohol intolerance and permission to use mustum must be given by the local Ordinary on a case-by-case basis.
  
  Additives
  
  Canon 924 §3 states the wine must not be corrupt, i.e. it is to be pure and natural. In the United States there are state-mandated additives to all commercially produced wines to act as an anti-oxidant which preserves the natural good condition of the wine and retards spoilage. Sulfides are added in such small amounts that the Holy See has had no objection to them, since their presence does not corrupt the wine. 
  
  Conclusion
  
  Any commercially produced wine (red, white or blush) may be used for sacramental wine so long as it falls within the parameters of being naturally made of grapes and having an alcohol content between 8% and 20%. The labeling of wine as “sacramental” or “altar” wine is a marketing strategy similar to that of “organic.” Any good house wine is fine and there are many good wines available in boxes or cubitainers, these have the advantage of lasting several weeks after opening because air is expelled and spoilage is retarded. Bottom line: the finer quality of wine, the better it is. This is an important consideration since the wine selected will become the Body and Blood of Christ.


Of further interest:

What is the largest winery that supplies sacramental wine to the Catholic Church?

Since when is white wine used in the Catholic mass?

A little note for "mustum" usage at Mass:


  Grape juice is not allowed for the Catholic Mass, but the use of "mustum" can be permitted. Mustum is a kind of wine that has an extremely low alcohol content. It's made by beginning the fermentation process in grape juice, but then suspending the process such that the alcohol content generally remains below 1 percent, far lower than the levels found in most table wines. (See: Q-and-A on the Vatican's recent instruction on bread, wine for Communion).