Where do we draw the line to define what drinks are valid to do Kidush (Shabbat)?
Does it matter if it says so on the bottle?
I saw that some bottle say "valid for kiddush" or something like this. I was wondering if all Kosher wines are valid, of if there is really something to it.
I'm marking this as community wiki, so anyone who has more information (and/or sources) please add it.
Some things to think about when choosing a wine for kiddush:
You must be able to say Borei Pri Hagafen on the wine (so it has to be made out of grapes). Manishewitz for example, makes some cherry wine, which is Shehakol (and says so on the bottle) and unfit for Kiddush.
There are some wines/grape juices that are mixed with water. This would not be valid for kiddush. The question here is if you add water to the wine, when do you say sheacol? There's a difference of opinion of maran and rama. It is well known that for many years the eda haharedit would give hechsher to wine/juice that has enough water in the mixture to be considered water for sefaradim. The Rav Ovadia would say that it is not only not casher for kidush but we say sheacol to drink. Because of this, today many wineries print that their wine/juice is also casher for havdala and kidush as the opinion of the maran habet iosef.
The wine should not be pagum (disqualified?) (See fn. 6 here). You can fix this wine by adding some more wine from the bottle (there are other ways to fix it as well, see Shulchan Aruch Orach Chaim 182:5-6). - If you have no other alternative it is better to make Kiddush on pagum wine, than not to make Kiddush at all (OC 182:7).
There is a discussion amongst Rabbinical Authorities whether wine that is Mevushal (cooked) may be used for Kiddush. The Rambam holds that wine must be fit to be offered on the altar in order to be good for Kiddush, and cooked wine may not be offered on the altar. As such, it may not be used for Kiddush. Others disagree. In practice maran in shulhan aruch mentions in three places than wine mevushal is casher (for kidush, avdala and 4 cups) (see here).
There is a discussion among Rabbinical Authorities whether grape juice may be used for Kiddush. (see here). And there is disagreement amongst modern Halachic Authorities whether reconstituted grape juice may be used for Kiddush. (see here)
My understanding is that when it says "Kosher for Kiddush" on the bottle, it is just letting you know that it is at least mostly grape product (if not %100 grape) and nothing more. It should also say Mevushal or non-Mevushal on the bottle.
Any kosher wine (or grape juice) can be used for kiddush. During Pesach make sure it is kosher for Pesach (usually the case, but check).
Some hold that you can use drinks other than wine if you cannot have grape products. There doesn't appear to be consensus on this, so consult a rabbi.
I have been taught that if wine or grape juice is not available, one can make kiddush on bread. (Of course, you have to change bracha, as with other substitutions.)
Edit: I'm leaving this here because of the attached comments, but the community wiki answer (which wasn't yet here when I posted) is much better. Go there. :-)
