Food & Drink

Homemade hard apple cider - estimating alcohol content from starting sugar weight

  • Last Updated:
  • May 27th, 2020 8:52 pm
[OP]
Member
Nov 14, 2012
369 posts
238 upvotes

Homemade hard apple cider - estimating alcohol content from starting sugar weight

I make simple and cheap home made hard cider by dissolving about 1tsp/1L baker's yeast in cup of lukewarm apple juice and then mixing it in rest of AJ. It creates a lot of fizz, so leave the cap slightly loose. In 1 day its already boozy, fizzy and still sweet, in two days is less sweet and more boozy, in 3 days is not sweet anymore and maximum boozy. Add sugar if you want more alcohol, but I prefer it on day 2. Tastes little bit like fruity beer or radler, it is very refreshing when cooled. Baker's yeast and brewer's yeast are same species of bacteria Saccharomyces Cerevisiae, but brewer's yeast was cultivated to tolerate higher alcohol content, baker's yeast dies out at about 9-10%, brewer's yeast goes much higher, some varieties even up to 25%

Would like to know alcohol content of my drink and do not have hydrometer, so I am going to use fermentation formula. I am not a chemist, so I may be completely wrong, but here goes:

Fermentation: glucose C6H12O6 → 2x ethanol C2H5OH + 2x carbon dioxide CO2

Molecular weight of glucose is 180.16 g/mol, ethanol 46.07g/mol and carbon dioxide 44.01 g/mol. That means 51% of glucose weight ferments to ethanol, 49% to fizz. To make it simple and easy to remember when shopping for juice, lets say half mass of sugar becomes ethanol. Btw. you can always add more sugar, although I prefer not to.

Looking at my current apple juice Nutrition Facts, President's Choice 100% AJ lists 31g sugar per 250mL, simplify 1mL => 1g, so 124g sugar per kg of juice => half mass of sugar becomes ethanol, so 62g of ethanol per 1kg of drink, i.e. 6.2% when fully fermented.

Final formula is

Alcohol Content [%] = Sugar Content per Liter [g] / 20
Last edited by ramon2 on May 27th, 2020 9:01 pm, edited 1 time in total.
.
1 reply
Deal Fanatic
Aug 29, 2011
6083 posts
3156 upvotes
Mississauga
Sugar is a disaccharide composed of glucose and fructose so you’ll need to adjust your stoichiometry accordingly.

Also, you’re assuming 100% conversion which in real life won’t happen.

(Ph.D. chemist over here Smiling Face With Open Mouth And Smiling Eyes)

Top