Ginger and yeast

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
------     ------------------------           
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".

I am researching a couple of recipes for making your own yeast that I have from the 1910's and 20's that both have ginger in them. And another little comment in a set of cookbooks from the 50's that says ginger helps to activate the yeast and make it rise faster.
I haven't tried it yet but I will be experimenting with it.

I don't think the Ginger helps activate the yeast. In fact, ginger has anti-fungal properties, and as yeast is a very simple fungus, it seems very unlikely to particularly thrive in the presence of ginger.

I don't think it's reputed to be outright bad for yeast like cinnamon is, but it is supposed to kill other fungi.

I also looked into the chemical components of yeast nutrients for brewing (baking and brewing yeast being so similar as the be almost indistinguishable in most uses), and couldn't find anything listed as a desirable nutrient that matched up to what ginger brings to the table.

Yeast grows at an exponential rate until its fermentation poisons catch up with it and start inhibiting growth. Ginger acts as a buffering agent in small quantities. Very small quantities. A buffering agent controls the pH of the dough. As long as the dough pH remains within a certain range, yeast will continue to grow at an exponential rate. The effect of small amounts of ginger added to the dough can shorten rise time approximately 50 percent. it also improves the quality of the rise, giving smaller, more consistently sized bubbles. The key here is very small quantities. I never use more than a pinch, added to the initial proofing of the yeast mixture.

Ginger as a stand-alone has no real affect on yeast. However like ginger, anything that contains ascorbic acid helps yeast activate and even more, helps the bread maintain it's shape and height. Ascorbic acid is nothing more than vitamin C. You can buy raw ascorbic acid from a pharmacy or even check your instant yeast. It probably has ascorbic acid already in there!

Recommendations: for every three cups of flour in a recipe, use 1/8 teaspoon of ascorbic acid. Also, AP flour is NOT a good substitute for bread flour! The gluten is needed to make the bread endure rising and punch-down then formation of the loaves. AP just doesn't have it.

I grew up in a French bakery, I went to a French chef school and mastered baking. I know what I am talking about!