Sugar source and alcohol content in Ginger Beer

Made my second batch of ginger beer the other day, and not sure if different sugars perhaps produced a little more alcohol..

For my first batch, I used 2 cups of pure cane sugar and 1 packet of dry champagne yeast from red star to yield ~1 gallon. I let the bottles sit at room temperature for a little more than a day, then I dropped them in the fridge.

For my second, I doubled the batch, but instead of 4 cups of sugar , I used 3 cups, and ~13 oz. pineapple juice (Reed's uses pineapple juice, so thought I'd give it a try). I also added the cane sugar by making a simple syrup this time to make sure it all dissolves, as well as added some lime--neither of which should have an effect on fermentation(?). I pitched the same red star yeast after letting my pot sit in the fridge for a few hours to cool.

--Edit: I used 1# of ginger/gallon yield and 1 lemon for both. Those didn't change between batches.

I bottled it all yesterday and ran out of bottles (beer's taking them all up!) so I poured the left overs into a Nalgene bottle which I took to work today to see if it's carbonated. To my surprise/satisfaction, when I opened the bottle it announced with a nice 'tssh!' that it was nice and fizzy. However, after drinking a pint's worth, I'm pretty sure this batch is...different.

As a beer-brewing, red-blooded, beard-adorned American, I can tell when I've had alcohol, and I'm 95% sure this ginger beer is a little more 'special' than my first batch. Given I just ate lunch prior to drinking it, it must have at least 2% alcohol to make me even notice anything, or even think about it. My beer brewing experience says this doesn't make much sense, but then I remembered the key difference between this batch and the prior, and one thing I learned from nutritional science in college: fructose is the simplest of sugars, and pineapple juice packs a lot of fructose. The champagne yeast is probably having a party with the stuff--and I'm actually enjoying my Monday at work.

Does that at least pass the smell test? Could champagne yeast have turned that much sugar into a noticeable alcohol content in less than 24 hours? Is there that big of a difference between cane sugar, and fructose? Or was there potentially some weird fungus growing on the ginger root that I used, explaining my general euphoria at work today?

Topic ginger-beer soda alcohol-content homebrew

Category Mac

1
answered at

Ignoring the other ferementables (lime and pineapple juice) 3 cups of sugar weights about 600g - or 1.32lb.

Table sugar has a potential of 1.046 points per pound per gallon, which gives an estimated SG of

46 x 1.32 / 2 = 30 gravity units

So your ginger beer would have had an initial SG of 1.030.

I plugged these figures into BeerSmith, which computes the estimated FG at 0.993, and a maximum abv. of 4.8%. (Actual abv. may have been lower if not all the sugar was fermented, or it may have been higher since this figure doesn't include the pineapple juice.)

So, your ginger beer could have been 4.8% abv - no wonder you had an enjoyable day at work! :)

Update: Yes there's a good chance the yeast will have worked their way through the sugar. When one makes a 1.030 SG starter, it can be fermented out within 24 hours, and that's with a complex wort. Your solution was mainly sucrose, which can be fermented fairly quickly - the yeast have to synthesize invertase to invert the sugar. However, fermentation could have gone even quicker if you boiled it with the lime juice and/or pineapple juice since this will provide the heat and acidic environment needed to invert the sugar syrup, turning it into fructose and glucose, which are immediately fermentable.

So, yes, it's quite likely the yeast worked their way through most if not all the sugar.

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