We use cookies to give you the best experience possible. By continuing we’ll assume you’re on board with our cookie policy

Experiment to Determine Acidities of Wine Essay Sample

The whole doc is available only for registered users OPEN DOC

Get Full Essay

Get access to this section to get all help you need with your essay and educational issues.

Get Access

Experiment to Determine Acidities of Wine Essay Sample

The purpose of this experiment is to determine the total and volatile acidities of each of the wines and compare them.

Acidity is a major contributor to the taste of wines. This is especially important in white wines, because there are very little tannins found in it, so acidity can affect the taste of the wine much more than in red wines.

In this experiment, 0.1M Sodium Hydroxide solution is needed for titrations. Because this is not a standard solution, it is first standardised using oxalic acid.

In order to calculate the total acidity of the wine, a titration with 0.1M sodium hydroxide is carried out with a pH meter. The pH of the wine and sodium hydroxide solution is measured when a certain volume of NaOH is added each time, and a titration curve of volume against pH is plotted. The volume for the solution to reach a pH of 8.2 is recorded. This is because NaOH is a strong alkali and wine is a weak acid, so the pH lies more to the side of the alkali. A pH of 8.2 as the equivalence point is a value agreed on by winemakers.

In order to calculate the total acidity of the wine, a representative acid must be used. This must be chosen because wine contains multiple different acids, which require different moles of NaOH to neutralise them. Tartaric acid was chosen as the representative acid for the wine, because it is thought to be the most abundant. Tartaric acid requires two moles of NaOH for it to be neutralised.

In order to calculate the volatile acidity of the wine, a sample of wine is evaporated using a steam evaporator, then made up to the original volume with deionised water and this process was repeated. The volatile acids evaporate away, while the remaining acids constitute what is known as the fixed acidity of the wine. This is made up to the original volume with deionised water and titrated with NaOH as before to give the acidity of this solution, which is known as the fixed acidity of the wine.The representative acid used here will again be Tartaric acid. In order to calculate the volatile acidity of the wine, this value is subtracted from the value calculated for the total acidity in part one of the experiment.



* Oxalic Acid

* Sodium Hydroxide

* 3 white wines from different regions

* Deionised Water

* Phenolphthalein Indicator


* Burettes

* Steam Evaporator

* Evaporating Basin

* pH Meter

* Pipettes

* Beakers

* One Litre Volumetric Flask

* 25cm3 Volumetric Flask

In order to standardise the sodium hydroxide solution, solutions of both oxalic acid and sodium hydroxide had to be made up.

To Make up Oxalic Acid solution

In order to make up the oxalic acid solution, 1.575g of oxalic acid was weighed out and dissolved in 100cm3 of deionised water. This was then made up to 250cm3 , so the resulting solution had a concentration of 0.05mol l-1 .

To Make up 0.1M Sodium Hydroxide solution

Because the formula mass of sodium hydroxide is 40g, 4g of NaOH was weighed out, and dissolved in 100cm3 of deionised water. This was then made up to one litre, in a volumetric flask, and the resulting solution should have a concentration of 0.1mol l-1

Standardising the Sodium Hydroxide solution

In order to standardise the NaOH solution, 20cm3 of Oxalic acid was pipetted into a volumetric flask and a few drops of phenolphthalein was added.

Sodium Hydroxide was then put into a burette, and the a titration was carried out until the phenolphthalein changed colour from colourless to pink, as this indicates the end point of the titration. A rough titre was carried out, and a further two titrations were carried out, in order to have concordance in the volumes ie two volumes within 0.1cm3 of each other.

To determine Total Acidity

1 – pH meter 2 – Burette 3 – Magnetic stirrer 4 – Stands 5 – Beaker with wine

100cm3 of wine was measured out using a burette and placed into a beaker, along with a magnetic stirrer. This beaker was placed onto a magnetic stirring plate and the plate was switched on, causing the magnetic stirrer to spin.

A burette was filled with NaOH and the pH of the wine was recorded before and had been added.

At the start of the titration, the pH was read after every 3cm3 of NaOH was added, but as this came closer to the equivalence point of pH 8.2 this was read more often.

A titration curve of volume against pH could then be plotted and the volume for the wine to reach a pH of 8.2 was determined. Using this and Tartaric Acid as the representative acid, the total acidity of the wine could be calculated, in mol l-1 , with regards to the Tartaric acid.

To determine Volatile Acidity

1 – Steam Evaporator 2 – Evaporating basin with wine

25cm3 of wine was measured out using a burette then placed in an evaporating basin. This evaporating basin was then placed on the steam evaporator and the wine was evaporated until very little remained.

This was topped back up to 25cm3 with deionised water, and this process was repeated twice, to ensure that all the volatile acids had evaporated away.

After the final evaporation, the remaining liquid was again made up to 25cm3 with deionised water, ensuring that the evaporating cylinder was thoroughly washed out, to ensure that all of the liquid was transferred.

This liquid was then transferred to a beaker, and a magnetic stirrer added, and titrated as above, using the pH meter to record pH against volume.

From this, a pH against volume titration curve could be plotted and from this the fixed acidity of the wine could be calculated. The volatile acidity of the wine could then be calculated by subtracting the concentration of the fixed acids from the concentration of the total acids.

We can write a custom essay

According to Your Specific Requirements

Order an essay

You May Also Find These Documents Helpful

Peculiarities of various assignment types

The educational process is diverse and full of interesting writing tasks which help students develop their academic abilities. Different assignments types are created by professionals in order to enhance students’ level of analytical, critical and writing skills and to vary the learning process. As a student, you will encounter numerous tasks of diverse complexities throughout your student life. Sometimes, maybe, too complicated! They have different peculiarities, structural...

Making decisions in health and social care

Critically analyses the concepts, features, and importance of costs and accounting in making decisions in health and social care Cost accounting is a method used in accounting to capture a company’s or organisation’s production costs. It assesses the input costs of every step in production, fixed costs like depreciation of capital equipment. Cost accounting measures and records costs individually then compare the input results via...

Сhildren development

Physical development 7-12 years By the age of 7 a child enjoys things such as bike riding and rollerblading they are now able to tie and untie shoelaces without adult help, they are now starting to understand what rules are and are able to follow simple rules. At 8-12 years a child improves the physical skills that they have already developed and start to see...

Forex international trading market

Introduction Forex exchange is on the rise in Namibia; resulting in more people wanting to learn how to trade to try to increase their income so that they can enhance their standard of living. Forex Foreign exchange identifies the process of converting domestic currency into international banknotes at particular exchange rates (Bofah, 2017, para.1). As the number of foreigners in Namibia is increasing, more Namibians...

Aristotelian idea of God

This image produced in 1544 shows emerging's of the Judeo-Christians and Aristotelian's traditions. Aristotle was very interested in the idea of motion and said “The world is in a constant state of motion and change”. An example of how the world is changing is the growth of trees and plants. Aristotle believed in a prime mover, which is the being which creates change in the...

Get Access To The Full Essay
Materials Daily
100,000+ Subjects
2000+ Topics
Free Plagiarism
All Materials
are Cataloged Well

Sorry, but copying text is forbidden on this website. If you need this or any other sample, we can send it to you via email.

By clicking "SEND", you agree to our terms of service and privacy policy. We'll occasionally send you account related and promo emails.
Sorry, but only registered users have full access

How about getting this access

Become a member

Your Answer Is Very Helpful For Us
Thank You A Lot!


Emma Taylor


Hi there!
Would you like to get such a paper?
How about getting a customized one?

Couldn't Find What You Looking For?

Get access to our huge knowledge base which is continuously updated

Next Update Will Be About:
14 : 59 : 59
Become a Member