From Cookwise, there's a table given from Wright, Bice and Fogelberg's "The Effect of Spices on Yeast Fermentation" from Cereal Chemistry, March 1954. where amount is the grams of the given spice with 2 grams of sugar and 1 gram of yeast in 30 ml of water, and the change in yeast activity is measured in ml of gas increase in 3 hrs. Here's the section for ginger:
Amount Change in Yeast Activity
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0.1 + 87
0.75 +172
1.0 +136
2.0 + 72
Of course, cinnamon shows an even larger increase at the 0.1 gram addition (+103), it just starts hindering at larger increments.
update : and to answer the second part of the question; Cookwise only listed a few additives (cardamom, cinnamon, ginger, dry mustard, nutmeg, and thyme), and they weren't all tested in the same amounts; the only two that were inhibiters were cinnamon in larger amounts, and dry mustard (for which they only had one point). It's possible that there was more in the original article, as the lead-in to the table said "The accompanying table shows the effects of some of these spices".
If you want a stronger flavor, and more bite, add more ginger. I make a dark, spicy ginger beer. I do not use yeast, but rather force carbonate. I don't know the exact quantities of ingredients used, I just make to taste each time.
Below is my ingredient list:
- Fresh grated ginger
- Peppercorns
- Molasses
- Cane sugar
- Fresh squeezed lemon (added after the mixture has cooled)
Molasses: Give the brew a thicker taste and darker caramel color, leave it out if you want it milder.
Ginger: Fresh ginger is key, don't use the powdered stuff. The more ginger you add, the spicier and more bitter it will be. You may need to increase the sugar content a bit too.
Lemon: This adds a nice zing.
Peppercorns: It may sound a little bit odd, but the peppercorns go very nicely with the ginger and lemon. Just add these to taste when you throw in the ginger.
I've also experimented with different types of sugars like Maple Syrup and Palm Sugar. Those each impart different flavors and may be worth trying too.
Best Answer
Short answer: kinda-sorta, in a weak way.
Long answer: European wild ginger is grown as a ground cover, not for culinary purposes. It is closely related to American Wild Ginger, though, which can be used to cook with, but it has a weaker flavor than Chinese ginger, less pulp, and you shouldn't actually eat the roots. I would presume European ginger to be a very similar experience, but only have experience with the American variety.