I'm a home brewer and have been to Europe several times just to drink beer (and see a few sights between beers). No brewery adds preservatives to beer here or there. The caveat is that hops are a preservative and flavor enhancer. People used to drink beer and wine instead of water because it was safer - the alcohol killed the bacteria. Hops is not so much a preservative as a flavor stabilizer. Of course with all the hop breeding programs now, hops contribute a lot more to the flavor than ever before. Carbonation is more related to beer style than region. The high end of carbonation would be saisons and weiss beers. Pilsners here and in Europe will be about the same. Ales will have a little less and porters and stouts less still.
Cheers
I think you'll find that the carbonation will generally be higher in bottled/canned beer than in tap beer, and can be somewhat reduced by pouring the bottled/canned beer into a glass, but will still be higher than a kegged beer poured into a glass.
My bachelor neighbor at the airport got into brewing about 10 yrs ago. He started with a home brew kit he got for Christmas, and bottled it into about 2 cases, and shared it with his neighbors at beer-thirty in the late afternoons/evening hours when all flying was done for the day.
Eventually, as his beer became popular, and bottling got old, it grew into him buying a 20 gallon boil pot, a 10 gallon mash tun, several 5 gallon Carboy's for fermentation, several 5 gallon kegs, and a CO2 bottle. He converted an old full sized fridge into a kegerator with a couple of taps coming out the side.
He recruited me to help him on brew day, which was a full day process. We would do a batch about once a month or so which started with 17+ gallons of water, 25lbs of Briess two row malted barley, 2lbs of carmelized barley, brewers yeast and Falconers Flight hops, after which we would end up with about 12+ gallons of beer in about 2-3 weeks.
We found we could make a really nice IPA that was pretty hoppy, but not too bitter if we dry hopped the beer with about half or more of the hops added after the first week of fermentation in the Carboy's rather than adding them all during the boil of the mash, which would bring out too much of their bitterness. It would usually end up about somewhere between 7 & 8% ABV. Needless to say, his hangar became quite the popular place for the locals in the late afternoons / evenings. This went on for several years until he found a new sweetheart who owned a bar & grill in a small SD town, and moved out there. Lots of good memories, but life goes on.
