Ginger Beer ABV from Bakers Yeast

Question

I’ve made ginger beer a few times. I usually make it with just fresh ginger and raw honey. Usually the I get well less than 2% ABV. This last week though I used a different honey, sourced from a farm, it was really raw and had a distinctly wild honey smell. After making the cordial and allowing to cool I mixed with water in my brewing vesseI and used 12g ~ 0.42 oz of bakers yeast, I made roughly 6GAL / 20L worth. IG = 1.046 and after 4 days, SG was 1.014 !! That’s 4,2% ABV, after 4 days controlled at 21C / 70F.

1. Could Honey as the sugar base really be that effective to convert to alcohol that quickly?

2. Can bakers yeast create that much alcohol?

Is this right, what is wronge where?

Answer 1

The sugars in honey are primarily fructose (38%) and glucose (32%). These are simple sugars, so bakers yeast will happily ferment it.

As @Dave mentioned in a comment, for a lot of intents and purposes (except actual beer brewing) bakers yeast is identical to brewers yeast... and as I have posted before, it wasn't until single-cell yeast cultures were made by Emil Hansen in the 1890s that bakers yeast was exactly brewers yeast.

I have made mead with bakers yeast which reached ~10% AbV. It can easily ferment to 8% AbV.

I suspect something went wrong with your first batch. Maybe the yeast had poor viability, it became too cold, too hot, there was some anti-microbial preservative in the honey (that would be unusual I guess), etc.

EDIT: since you are making a ginger-mead, maybe including some yeast nutrient would help fermentation. Honey (and sugar-water) does not contain much in the way of minerals for optimal yeast health.

Answer 2

Bakers yeast can certainly create that much alcohol (and more) because it is the same kind of yeast as brewer's yeast (S. cerevisiae). You mentioned in a comment that as far as you know, the honey was the only change in your usual process. As we discussed in the comments, you might want to suspect the new honey could be perhaps adulterated with some kind of simple sugar like glucose, which is a serious issue in the honey industry; however, since the honey smelled pretty raw and wild to you, my guess is that this is not the issue here.

My best guess is that this new honey has a higher proportion of fermentable sugars than the honey you normally use. If you look at the composition of honey in the US, you can see (Table 1) the variability in the sugars from type-to-type. If you get the chance to make another batch with honey from this farm, it would be very interesting to see whether you get another batch with the higher level of alcohol.