Biology
The alcohol content of wines
Author
Cécile Bardel, Charles Baudelaire
Target Group
16-17 years old students
Brief Description
The alcohol content of wines

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THE ALCOHOL CONTENT OF WINES 

Topic Handout (1/2)

Overview and research to carry out

The climate is an essential part of viticulture. Global warming, responsible for an increase in temperatures linked to greater levels of sunshine and less precipitation, affects the sugar content and acidic levels of the grapes, and by extension, the quality and taste of the wines.

In this way, wine contains more alcohol today than it ever has in history. For example, the French Château Latour of 1959 contained only 11.6% alcohol whilst the 2009 vintage was at 13.9%. Throughout the world, it is difficult to find wines with an alcohol content under 13%.

 

The aim is to show that the alcohol content in wines is determined by the sugar content.

Resources

Yeast cells carrying out the fermentation of alcohol7TzqFAoFAqF+cGmEGGhUCgUCvOKIsJCoVAoXIExD

Wine is a drink produced exclusively from the complete or
partial alcoholic fermentation of grape.
Step 1: Plan an experiment to help to resolve the problem (Time allowed: 10 minutes)

Come up with a feasible experiment allowing you to show that the alcohol content in wines is determined by the sugar content.




THE ALCOHOL CONTENT OF WINES 

Topic Handout (2/2)

Step 2: Carry out the experiment to obtain exploitable data

Carry out the computer aided experiment on the amount of ethanol produced as a function of the quantity of sugar in the grape juice to show that the alcohol content in wines is determined by the sugar content.

Step 3: Process the data and present your findings
In the form of your choice, process and present the raw data so that you have the necessary information to respond to the problem. 
Step 4: Used the obtained results to respond to the problem and answer the question

Process the results to show that the alcohol content in wines is determined by the sugar content.





THE ALCOHOL CONTENT OF WINES 

Experiment protocol handout

Equipment available and protocol for using the equipment

Material

 

-          Computer assisted recording equipment: calibrated ethanol sensor

-          Instructions for using the computer equipment

-       Suspension of baker's yeast (10g/L), oxygenated and deprived of nutrients for 24 hours

(put the yeast in distilled water with an oxygen source (bubbles) the day before so that they exhaust their nutritional reserves)

-          Grape Juice

-          Grape Juice with added sugars

-          A 25ml syringe or pipette to remove the yeast

-          Two 1 ml syringes to remove the grape juice

-          A small beaker of distilled water (put the yeast in)

-     A waste disposal bin/receptacle to collect the liquids

To show that the alcohol content in wines is determined by the sugar content:

-          Fill the measurement enclosure with the yeast suspension and 0.5ml of grape juice

-          Place the ethanol sensor in the mixture and start recording

-          Duration of the recording: 6 minutes

-          Restart the recording adding 0.5ml of the grape juice with added sugars

Health risks: Nothing to report 

Handling precautions       

        -      Ensure the absence of air bubbles when closing the enclosure.

        -      Save the first recording before starting the second.

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THE ALCOHOL CONTENT OF WINES 

Lab sheet for the teacher

Equipment for the student:

-          Computer assisted recording equipment: calibrated ethanol sensor

-          Suspension of baker's yeast (10g/L), oxygenated and deprived of nutrients for 24 hours (put the yeast in distilled water with an oxygen source (bubbles) the day before so that they exhaust their nutritional reserves)

-          Grape juice

-          Grape juice with added sugars (add 10g of glucose or saccharose per litre of grape juice)

-          A syringe or a pipette of 25ml to remove the yeast

-          Two syringes of 1 ml to remove the grape juice

-          A wash bottle of distilled water

-          A waste disposal bin/receptacle to collect the liquids


Additional materials:

-          Accessible on the site: http://pedagogie.ac-toulouse.fr/svt/serveur/bankact/ : instructions for the computer software  

 

Bibliography for the alcohol content in wines: Pour la science  Mai 2015 - n° 451, réchauffement climatique, le goût des vins va-t-il changer ?




THE ALCOHOL CONTENT OF WINES 

Expected result

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Related files

expected result for the experiment 177 KB
The Alcohol Content of Wines 328 KB
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