Need help from my fellow homebrewers!!!

hello everyone, i am conducting an experiement in my molecular biology lab where i will be measuring the rate at which yeast reduce the concentration of sugar in solution. the protocols call for a 24 period where i will be taking samples every 3 hours. so my question to everyone is should i pitch yeast prior to the 24 observation period? or pitch and then stat measuring. i want good conclusive data and do not want no change samples due to lag time. what does everyone think?! im using table sugar at 1.040 and probably notty. if anyone knows of a quick starting yeast that would help too. how long would it take for this to ferment out? thanks in advance everyone!

The yeast will not eat anything for the first 12-18 hours because it is in its reproductive stage. I would pitch it before the 24 hours to give it time before it starts eating. If you are using the same yeast and wort volume for both batches, I would imagine the reproductive phase will be the same length.

As far as how long will it take? That depends on many things such as temperature and volume of the wort. If it were small (1000 ml or less) it very well may ferment out in 24 hours.

Why not include the time it takes for fermentation to begin showing measurable results in your data set?

Then begin the 24 hour observation period once that begins.

as a scientist i would say you want measurements before you pitch, then at pitching and then every 3 hrs. If you really want to be scientific you need to also have a control brew with no yeast to measure possible degredation and wild yeast and bacteria that may consume a small amount of sugar. But taking before during and after will give you a nice S shaped curve

what's this experiment supposed to be showing, cuz you will have lots of variables, particularly pitch rate and temperature, that are going to effect the rate they reduce? If none of that other stuff matters, I'd just take one prior to pitching, then every few hours once you do.

the rate and temp will be the same for both. im trying to mainly show that yeast reduce sugar concentration and br able to measure the decrease using spectrometry. if i make say 500 ml and pitch half a packet of notty into both will i get data points in the first 24?

the only way i can imagine this experiment working is if you put a hydrometer inside a clear fermentor of your choice, and never open that fermentor! Not sure how to determing the % of fermentable sugar, or how to read a hydometer if the beer makes to much foam...

you'll definitely get data points within the first 24 hours, it may even be done fermenting, if you used that size and OG. you'd be 30x over pitching a 0.5L at 1.04 with 5.75g of notty, i.e. little lag time

oh also, don't forget to kill the yeast once u pull the samples otherwise your data will be skewed

thanks guy i think i will over pitching because im going to up for 24 hours! so as long as i get atleast 5 data points im good. i had some styrafroam floats that i will be boiling the 1 ml microcentrifuge tubes.

cool, do you mind posting the curve after? I'm interested in seeing what it looks like

for sure i will im also making a standard curve of known glucose concentration to figure out the concentration of my samples.