Adding priming sugar to an
ale doesn't break the
Reinheitsgebot but you must list the ingredient in the ingredients list. Also, if you are a brewer in Bavaria or Baden–Württemberg you cannot add sugar to an Ale in any case (Bavaria and Baden–Württemberg have more restrictive rules than the rest of Germany).
You cannot add lactic acid to the mash, but you can buy Weyermann malt which is sprayed with lactic acid, that's compliant with the
Reinheitsgebot.
You cannot add gypsum and calcium chloride to the mash, but you can add those salts to the brew water (see the difference?! One is
rein, the other isn't!)
You can use hop pellets and hop extract if the solvent is natural (such as good old alcohol, and why should one want to use anything else, one might ask).
You can use microplastics (PVPP) but you must filter it with mechanical filters (such as diatomaceous earth) just like anywhere.
You can use chlorinated water, that's
rein.
You can use hops during boiling or before boiling, that's
rein, but you cannot use hops during or after fermentation (dry hopping), that's not
rein.
"Zinc cannot be provided directly by addition of ZnSO4 or ZnCl2, but running the wort through piping or over lauter screens containing zinc can provide the needed trace amounts "
Carbon dioxide for beer carbonation must come from fermentation, that's
rein. Carbon dioxide with a different origin can be used for moving and serving beer, that is OK.
https://www.morebeer.com/articles/R...Law_Bavaria_1516_Malt_Barley_Water_Hops_Yeast
[If that reminds you of Kosher or Halal rules, you are not alone

]