Science Experiment with yeast - Home Brew Forums
Register Now For Free!

Home Brew Forums > Home Brewing Beer > Brew Science > Science Experiment with yeast

Thread Tools
Old 08-14-2012, 02:48 AM   #1
Dec 2010
pembroke, ky
Posts: 46

I want to do a science experiment with my kids this weekend and I was thinking about using some cheap yeast to show how different types of sugars ferment or do not ferment. I didn't see anything that had a break down of the different types of sugars and how yeast would interact. Is there already a post on this or could someone smarter than me explain. I would like to explain the chemical break down of the sugars a little and what components caused the different reactions. I planned on using simple bakers yeast so that I don't waste any of the good stuff on water bottles and ballons. Any help will be appreciated.
Thanks, Nick

Reply With Quote
Old 08-14-2012, 11:14 PM   #2
Aug 2010
McLean/Ogden, Virginia/Quebec
Posts: 9,663
Liked 1604 Times on 1222 Posts

You don't have too many sugars available to you: maltose and glucose from the LHBS, sucrose from the grocery store which might also have fructose (in the form of high fructose corn syrup), and perhaps invert sugar (Lyles Syrup) so it will be hard to illustrate that, for example, lager and ale yeasts ferment rafinose and mellibiose differently.

For the chemical process of fermentation (which is really quite involved) look up glycolysis in any biochem text or try the Wikipedia article.

With bakers yeast and table sugar I'm not sure you could do much except note how the reaction starts slowly, picks up speed and drops off, show how colder temperatures slow it down, demonstrate (by using grape juice for example) that the sweetness drops and other flavors emerge, distill off some of the alcohol (you can buy little stills from novelty catalogs). Bakers yeast will doubtless rip through glucose faster than an equivalent amount of sucrose as glucose enters EMP (the glycolytic pathway) directly where as the yeast have to synthesize a transportase to get sucrose into the cell, invert it and then send the fructose down a separate (partially) pathway.

Reply With Quote
Old 08-14-2012, 11:18 PM   #3
H-ost's Avatar
Jul 2011
Bellevue, WA
Posts: 1,746
Liked 72 Times on 53 Posts

John Palmer breaks it down pretty well in his book "How To Brew".

There is a free version online at
"Wisdom isn't "thinking hard". It's experience." - PassedPawn

Reply With Quote
Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
Degassing Science? mpelechaty Brew Science 19 12-24-2011 05:28 AM
The SCIENCE of off-flavors... year2beer Brew Science 28 12-11-2011 04:32 PM
Brew Science Plus ChemEMc Brew Science 4 12-09-2010 12:10 AM
The science behind No Chill Edcculus Brew Science 31 07-25-2009 03:45 AM

Forum Jump