TITRATABLE ACID OF ALCOHOLIC
BEVERAGES
Total Titratable Acid of Alcoholic Beverages
Aim: To find the total titratable acid in wine to determine what packaging has the best
preservability and quality through balancing of sugars, acids, and fruit flavours.
Introduction
Variable geographical, geological, climate and
whether are known as “terriors” when discussing
factors that influence the ratio between acid and
sugar in ripening fruits, creating distinctive features
in flavour (Vinepair, n.d.). The fermentation process
allows a redox reaction to occur as the yeast reacts
with glucose in fruit juice to undergo glycolysis to
produce pyruvic acid in anaerobic respiration (Alba- Figure 1 Diagram of Glycolysis
Lois et al.,2010). During this fermentation,
nicotinamide adenine dinucleotide (NAD) in its oxidation or reduced state NAD+ and NADH
respectively. Via acetaldehyde does this redox reaction take place to form either ethanol or
carbon dioxide (CO2) (Liu et al., 2017) (Fig 1).
Terriors affect the balance between the acid, sugar and fermented alcohol. Generally
warmer climates will cause grapes to yield higher sugar concentrations and low acidity, whilst
cold climates will produce grapes with greater
acidity in their ratio (Puckette, 2015). Both
climates can produce good or poor-quality wine.
The main difference between low- and highquality wine is the timing of when the grapes are
harvested to have the most desirable acid to
sugar ratio. Generally, acceptance ratings from
consumers decreased with higher acid Figure 2 Graph showing the correlation between
acid concentration in wine and consumer
concentrations (Fig 2) (Jayasena et al., 2007).
acceptance rate
“Flavonoids” are polyphenols that are
another key component in determining the quality of grape wine. Through phenolics, wine
texture and mouthfeel can enhance from its function as metabolites (Gawell et al., 2014).
Anthocyanins (pigments), flavanols (UV protectors) and tannins fall under the flavonoid
category, each subject to biosynthesis, accumulation and degradation change from high
temperatures in particular (Gouot et al, 2019).
Whilst pH and titratable acids (TA) both measure acids (titratable acids in molarity
[moles/litre]), pH indicates the hydrogens’ ability to disassociate, however TA measures the
total amount of disassociated hydrogen protons (Tyl et al., 2017). pH gives a better
understanding of microorganism’s ability to grow in foods while the TA indicates the impact of
organic acids on foods, and flavour characteristics of wine (The Australian Wine Research
Institute, n.d.). Although both measure acids, there is no direct predictability between the two
measurements.
The ratio between acids and sugars in ripening grapes is
crucial as the glucose in sugar ferments into alcohol, and TA
contribute to preservability and sensory characteristics of wine
(most prevalent in wine are tartaric acid, malic acid, and citric
acid) (Rajković et al., 2007). Microbial degradation will be
hindered with the presence of acids as high pH will promote the
growth of spoiling microbe (Shanker et al., 2021). Acids act as a
preservative as pathogens die at a pH below 4.7, however only
weak acids “inhibit the growth of the microbe in its undissociated
forms at low pH conditions” (Shanker et al., 2021). Although high Figure 4 Diagram of Tannin
acidity is not beneficial to the flavour profile of wine, it allows Polymer in Chain
wines to be aged which will in turn provide a more
pleasurable wine with previously hidden flavours as
a result of continued fermentation in anaerobic
respiration (Krebiehl, 2018). As wine ages, tannins
lose their charge and form into larger chains (Fig 3),
falling as sediments to leave a smoother, rounder and
more gentle wine, however, if oxidised, the tannins
will depolymerize tannin chains, and their surface
area will increase (Krebiehl, 2018). The observed Figure 3 Scale Showing how Colour Changed in
colour reflects the aging process of wine as tannin Wine Over Time
chains grow larger, leaving less anthocyanintannin polymers, allowing colour change to occur
as anthocyanin (a flavonoid) functions in
changing pigment (Fig 4) (Russan, 2019).
The procedure of wine making (Fig 5)
further affects the quality and TA present. If the
wine is oaked, malic acid is converted to lactic
acid which is a softer acid, leading to a higher
quality wine (Brittain, 2001). Due to low pH and a
weak TA, microbes are not able to grow under
this condition, creating a wine that is more
preservable. Bottled and cask wine differ in
quality as acidity will vary during the shelf-life of
cask wine. Due the porous bags which contain the
wine, oxygen particles oxidise the wine resulting
in an expiration date for cask wine, whilst bottled
wine cannot be oxidised when unopened
(Johnson, n.d.). Oxygen’s high electronegativity
weakens O–H bonds through reduction by
Figure 5 Diagram of the Wine Production Process
drawing away electrons, increasing the strength
of acids (Chemistry Libretexts, 2020). Organic wines further differ in pH, as there is the absence
of synthetic chemicals in the grapes when ripening (Honan, 2015). As pesticides are slightly
acidic with a “pH between 5.5 and 6.5” (Winfield United, 2015) and herbicides are generally
acidic (Bechman, 2016), no artificial acids are introduced to organic grapes. However, as no
herbicides are used to alter soil pH, ideal conditions for grapes cannot be created. A controlled
soil pH of 5.5 to 6.5 provide the best growing conditions for grapes (Brown, 2013).
Furthermore, the growth of weeds draws nutrients from soil and slightly acidify it, leading to
the grapes to become more acidic, and in turn an increase in acidity for the wine (WalterPeterson, 2013).
When calculating total TA, ratio of different acids is unknown. As 90% of acidity in wine
is a combination of tartaric acid and malic acid one of these acids will be necessary during
calculations (Joye, 2019). The average percentage of total TA in fruits at early harvest are 56%
and 50% respectively whilst 57% and 45% during late harvest, hence, tartaric is the most
present TA (Kliewer et al., 1967). As Tartaric is the most present TA in the fruit and wine,
calculations are made assuming tartaric acid as the total TA, being expressed as g/L tartaric
acid.
Sulfur dioxide (SO2 ) and Carbon
dioxide ( CO2 ) affect titration after
reacting to water through the acidic
interference of Sulfuric acid (H₂SO₄) and
carbonic acid (H₂CO₃) respectively. The
impact of SO2 is negligible due to
minimal contribution, however, the
presence of CO2 can equate to errors
over 1g/L if sample is not degassed
(Iland, 2000). Additionally, as CO2 is
absorbed by the standard solution of Figure 6 Titration Curve with Carbon Dioxide Interference
alkali sodium hydroxide (NaOH), the
end point of an acid-base titration changes over time as sodium carbonate is produced,
weakening the NaOH with time (Shahorin, 2021). The presence of CO2 in a titration effectively
creates a new equivalence point (Fig 6) as the strength of a NaOH standard solution decreases,
and acidity increases when water reacts with CO2 to produce H₂CO₃.
The total TA of a wine signifies the quality and preservability through the balance
between sugars and fruit flavours inside. Therefore, the aim of this investigative is to determine
which form of wine is the best quality for consumers.
Results
Trial 1
Trial 2
Trial 3
Standardisation of NaOH with KHP
Initial Volume (mL)
Final Volume (mL)
0.600
47.60
0.550
48.20
0.200
47.80
Table 1 Table showing the standardisation of NaOH
Titre Value (mL)
47.00
47.65
47.60
Trial 1
Trial 2
Trial 3
Titration of Organic Wine
Initial Volume (mL) Final Volume (mL)
0.500
12.20
2.350
14.00
3.000
14.75
Titre Value (mL)
11.70
11.65
11.75
Table 2 Table showing volume to neutralise organic white wine
Trial 1
Trial 2
Trial 3
Titration of Bottled Wine
Initial Volume (mL) Final Volume (mL)
1.100
12.75
26.00
37.70
37.70
49.40
Titre Value (mL)
11.65
11.70
11.70
Table 3 Table showing volume required to neutralise bottled white wine
Trial 1
Trial 2
Trial 3
Titration of Cask Wine
Initial Volume (mL) Final Volume (mL)
26.95
40.40
1.600
14.70
29.30
43.00
Titre Value (mL)
13.45
13.10
13.70
Table 4 Table showing volume required to neutralise cask white wine
Calculations
Calculating the molarity of NaOH
KHP moles were found and divided by volume in litres to find concentration using formula:
𝑛
C=𝑣
Moles of KHP used in standardising was then found by multiplying concentration and volume
used in litres, giving the formula:
n=cxv
KHP and NaOH have a 1 : 1 molar ratio, therefore concentration of NaOH can be found
with the formula:
c=
𝒎
𝒗
where v is in litres, m is moles, and c is concentration in molarity.
Calculating the total TA in wine samples
Moles of NaOH used is calculated by multiplying the concentration of NaOH and volume
used in litres, giving the formula:
n=cxv
tartaric acid (C4 H6 O6 ) molar ratio to NaOH is 1 : 2, therefore half the moles of NaOH.
Concentration is then found using the formula:
𝑛
C=𝑣
Calculating the molarity of NaOH
Mass of KHP used: 2.5567
c(KHP) =
(
2.5567
)
204.22
0.250
c(KHP) = 0.050077M
n(KHP) = 0.050077 x 0.04742
n(KHP) = 0.002375 mol
Calculating the total titratable acidity of
bottled white wine
n(NaOH) = 0.095 x 0.01168
n(NaOH) = 0.0011096
1
n(C4 H6 O6 ) = 2 x n(NaOH)
n(C4 H6 O6 ) = 0.0005548 mol
c(C4 H6 O6) =
n(KHP) = n(NaOH)
c(NaOH) =
0.002375
0.025
0.0005548
0.025
c(C4 H6 O6) = 0.02219M
c(NaOH) = 0.095M (2sf)
c(NaOH) = 0.1M (1sf)
Calculating the total titratable acidity of
organic white wine
Calculating the total titratable acidity of
cask white wine
n(NaOH) = 0.095 x 0.0117
n(NaOH) = 0.095 x 0.01342
n(NaOH) = 0.001115 mol
n(NaOH) = 0.0012749
1
1
n(C4 H6 O6 ) = 2 x n(NaOH)
n(C4 H6 O6 ) = 2 x n(NaOH)
n(C4 H6 O6 ) = 0.00055575
n(C4 H6 O6 ) = 0.000637545
c(C4 H6 O6) =
0.00055575
0.025
c(C4 H6 O6) = 0.02223M
c(C4 H6 O6) =
0.000637545
0.025
c(C4 H6 O6) = 0.02550M
Figure 7 Calculations showing concentration of total titratable acids in various wines and NaOH
standardisation
Figure 8 Graph comparing concentration of each wine type
Discussion
The results of this experiment determined white wine stored in cask packaging had the highest
concentration of total TA with 0.02550M (fig 7). Bottled and cask had substantially less with
0.02219M and 0.02223M respectively, bottled having the least total TA (Fig 8).
The independent variable for this experiment was the control over the burette. As a
result, the dependent variable was when the alcohol would have been neutralised as a reaction
to how much volume of a base was added. Other variables which were controlled were the
maintenance of clean equipment, a dry pipette bulb, the amount of Potassium hydrogen
phthalate (KHP) used in degassing the unknown wine solution, and the volume of the aliquot.
These variables were controlled to ensure that each trial had the same conditions.
Given the background research, the results corresponded to which wine type would
have theoretically held the most and least total TA. Due to the porous bags used in cask wine,
oxygen particles weaken O-H bonds, increasing the strength of titratable acids over time,
indicating cask wine to yield the highest TA. Due to the lack of controlled growing environments
for organic grapes, higher acidity will be present as the soil will contain less nutrients and lose
pH, leaving organic wine to have a theoretically higher total TA than bottled wine. The slight
difference in TA between bottled and organic can be observed in figure 8.
Although results were concurrent to theory, improvements to more reliable and
accurate data could have been made. Given more time, additional trials could have been
conducted to obtain more accurate results. Furthermore, human error in titrating could be
reduced through an automatic titrator to increase the accuracy of burette for better detection of
the endpoint. Through better control over volume of standard solution used, calculations would
benefit through better data capture. Furthermore, with reliance on technology for quick and
accurate use of burette, more trials could be conducted as less time would be spent titrating.
Additional human error was made in
evaluating the end point of each titration. Colour
change from pale yellow to pale pink is subtle
and difficult to observe. With the use of green
paper underneath the aliquot, subtle colour
change was more observable (fig 9), however,
the colour change was still too subtle, causing
difficulty in finding multiple concurrent titre
values.
Furthermore, the presence of CO2
affected the ability to gather concurrent results Figure 9 Picture showing the colour of endpoint in
titration against green paper
as CO2 in the air is absorbed by NaOH to form
sodium carbonate, weaking the acid, altering the equivalent point over time as more volume is
required to neutralise the TA. As a result of the weaking base, the colour of the solution would
revert, making the end point difficult to determine. Different titre values were recorded during
the standardisation of NaOH (Table 1), meaning the instability of the solution. As the standard
solution was not stable due to the absorption of CO2 , the titration of the wines was made
difficult due to a wide range of results from the varying strength of NaOH. Only until three
concordant results were found could the total TA be discovered. Better degassing methods
could have been used to ensure the absence of CO2 in producing H2 CO2, affecting the acid
concentration in the aliquot. To minimise CO2 exposure, the titration should be conducted
under a vacuum and the aliquots should be degassed by a strong vacuum or to be heated briefly
boiled (Iland, 2000). De-ionised water should also be freshly boiled and cooled. With these
conditions, no CO2 would be able to affect the endpoint of the titration, resulting in more
accurate and concurrent results.
In determining the total TA, the volume of each acid in the aliquot should be known.
Tartaric acid was used to calculate the total TA due to it being the most predominant TA in
white wine. Finding the true total TA, the moles of each present need to be known to find the
accurate g/L of TA. Currently tartaric acid is used to give a general understanding of the
approximate total titratable acid present.
As bottled wine displayed the least TA, it is the best quality wine for consumers as its
ability for preservability is the best with the weakest acids, does not oxidise without being
opened, and as a result tannins would have the least surface area. Furthermore, with low TA, the
acid to sugar ratio is symbolic of quality wine, exhibiting terroir with grapes ripened in warmer
climates.
Conclusion
Through the experiment, the best quality wine is found to be in bottled wine. Organic displays
better wine quality than cask wine due to cask wine’s high total TA. Additionally, the low TA in
bottled wine displays optimal acid : sugar ratio compared to other forms of white wine..

References
Alba-Lois, L. and Segal-Kischinevzky, C., 2010. Yeast, Fermentation, Beer, Wine | Learn
Science at Scitable. [online] Nature.com. Available at:
<https://www.nature.com/scitable/topicpage/yeast-fermentation-and-the-making-ofbeer-14372813/> [Accessed 23 April 2022].
o

Bechman, T., 2016. Why you need to know about pH when spraying herbicides. [online]
Farm Progress. Available at: <https://www.farmprogress.com/story-why-need-knowph-spraying-herbicides-9-136707> [Accessed 21 April 2022].
o

This source explains how oxidation increases the strength of acids through the
weakening of O-H bonds.
Compound Interest. 2014. The Key Chemicals in Red Wine – Colour, Flavour, and Potential
Health Benefits. [online] Available at:
<https://www.compoundchem.com/2014/05/28/redwinechemicals/> [Accessed 26
April 2022].
o

Had a titration curve with how carbon dioxide created new equivalence point.
Chemistry LibreTexts. 2020. 16.10: Acid Strength and Molecular Structure. [online]
Available at:
<https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_A_Molecular_A
pproach_(Tro)/16%3A_Acids_and_Bases/16.10%3A_Acid_Strength_and_Molecular_Stru
cture#:~:text=Any%20inductive%20effect%20that%20withdraws,the%20strength%2
0of%20the%20acid.> [Accessed 25 April 2022].
o

This source explains the best pH conditions for the ideal grapes to grow.
Cark, J., 2002. pH curves (titration curves). [online] Chemguide.co.uk. Available at:
<https://www.chemguide.co.uk/physical/acidbaseeqia/phcurves.html> [Accessed 25
April 2022].
o

Explains how softer acids makes wines more palatable. It further explains how
malic acid turns into lactic acid.
Brown, D., 2013. Soil sampling vineyards and guidelines for interpreting the soil test
results. [online] MSU Extension. Available at:
<https://www.canr.msu.edu/news/soil_sampling_vineyards_and_guidelines_for_interpr
eting_the_soil_test_resul> [Accessed 21 April 2022].
o

Explains the chemistry of herbicides and how they are usually acidic, affecting
the acidity of non-organic grapes.
Brittain, H., 2001. Analytical profiles of drug substances and excipients. 28th ed. San
Diego: Academic Press, pp.153-195.
o

Explains glycolysis in fermentation and the role of pyruvic acid.
Had a graph of tannin chains of how the chain together and polymerise.
Gawel, R., Godden, P., Williamson, P., Francis, L., Smith, P., Waters, L., Herderich, M. and
Johnson, D., 2014. Influence of phenolics on white wine quality and style. Wine &
Viticulture Journal, [online] 29(3), pp.34-36. Available at:
<https://issuu.com/provincialpressgroup/docs/wvj_v29n3-v2_lr> [Accessed 23 April
2022].
o

Gouot, J., Smith, J., Holzapfel, B., Walker, A. and Barril, C., 2019. Grape berry flavonoids: a
review of their biochemical responses to high and extreme high temperatures. [online]
National Library of Medicine. Available at:
<https://pubmed.ncbi.nlm.nih.gov/30388247/> [Accessed 24 April 2022].
o

Describes why cask wine has a shelf life as the bags that hold the wine are
porous and allow oxygen particles to oxidise the alcohol.
Joye, I., 2019. Encyclopedia of Food Chemistry. 1st ed. [ebook] Guelph: Elsevier, pp.1-9.
Available at: <https://doi.org/10.1016/B978-0-08-100596-5.21582-5> [Accessed 25
April 2022].
o

Demonstrates consumer approval rating to a change of ratio between acidity
concentration and sugar concentration.
Johnson, M., n.d. 6 Must-Try Seltzers For The Summer. [online] Spoon University.
Available at: <https://spoonuniversity.com/lifestyle/five-must-try-seltzers-for-thesummer> [Accessed 23 April 2022].
o

Provides information on how to correctly titrate with external influences such as
the interference of carbon dioxide.
Jayasena, V. and Cameron, I., 2007. °BRIX/ACID RATIO AS A PREDICTOR OF CONSUMER
ACCEPTABILITY OF CRIMSON SEEDLESS TABLE GRAPES. [ebook] Perth: Department of
Agriculture and Food Western Australia, p.11. Available at:
<https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1745-4557.2008.00231.x>
[Accessed 27 April 2022].
o

Explains how organic grapes differ in acidity due to the lack of pesticides and
herbicides.
Iland, P., 2000. Techniques for chemical analysis and quality monitoring during
winemaking. 1st ed. Campbelltown: Patrick Iland Wine Promotions.
o

Explains flavanols and how they are affected by temperature.
Honan, D., 2015. Why you should be drinking organic wine and where to find it. [online]
the Guardian. Available at: <https://www.theguardian.com/lifeandstyle/australia-foodblog/2015/feb/07/why-you-should-be-drinking-organic-wine-and-where-to-find-it>
[Accessed 23 April 2022].
o

Explains flavanols and how phenols impact the quality and characteristics of
wine.
This source explains how tartaric and malic acid make up most acids in alcohols.
Kliewer, M., Howarth, L. and Omori, M., 1967. Concentrations of Tartaric Acid and Malic
Acids and Their Salts in Vitis Vinifera Grapes. American Journal Enology and Viticulture,
[online] 18(1), pp.42 - 54. Available at:
<https://www.ajevonline.org/content/18/1/42#:~:text=For%20all%20varieties%2C
%20the%20average,45%25%20at%20the%20late%20harvest.> [Accessed 25 April
2022].
o
Gives percentages of which acid is most dominant in grapes. Tartaric acid and
malic are the most present, however, tartaric acid has a greater percentage.

Krebiehl, A., 2022. What Really Happens as Wine Ages? | Wine Enthusiast. [online] Wine
Enthusiast. Available at: <https://www.winemag.com/2018/10/09/what-happenswine-ages/> [Accessed 23 April 2022].
o

Liu, C., Qin, J. and Lin, Y., 2017. Fermentation and Redox Potential. Fermentation
Processes, [online] Available at: <https://www.intechopen.com/chapters/51634>
[Accessed 24 April 2022].
o

Report which goes into detail the titratable acids present in wine and how they
affect the preservability and characteristics of it.
Russan, A., 2019. The Science of Color in Wine | SevenFifty Daily. [online] SevenFifty Daily.
Available at: <https://daily.sevenfifty.com/the-science-of-color-inwine/#:~:text=Tannin%2Danthocyanin%20polymerization%20in%20wine,result%20i
n%20a%20softer%20mouthfeel.> [Accessed 26 April 2022].
o

Describes why different acidity affects characteristics of the wine
Rajkovic, M., Novakovic, I. and Petrovic, A., 2007. Determination of titratable acidity in
white wine. Journal of Agricultural Sciences, Belgrade, [online] 52(2), pp.169-184.
Available at: <http://www.doiserbia.nb.rs/img/doi/1450-8109/2007/145081090702169R.pdf#:~:text=Wines%2C%20as%20a%20rule%2C%20contain,or%20ar
gol)%20during%20alcohol%20fermentation.> [Accessed 22 April 2022].
o

Gives the process of how white wine is made from grapes. Picture from this site
was used that gave the process.
Puckette, M., 2015. Understanding Acidity in Wine | Wine Folly. [online] Wine Folly.
Available at: <https://winefolly.com/deep-dive/understanding-acidity-in-wine/>
[Accessed 23 April 2022].
o

Says how cool climate and warm climates affect the sugar-acid ratio within
grapes.
Puckette, M., 2013. How White Wine is Made From Grapes to Glass | Wine Folly. [online]
Wine Folly. Available at: <https://winefolly.com/deep-dive/how-is-white-wine-made/>
[Accessed 25 April 2022].
o

Explains how NADH and NAD+ affects the process of fermentation, undergoing
redox reaction.
Mowery, L., 2018. The Real Difference Between Cool-Climate and Warm-Climate Wine |
Wine Enthusiast. [online] Wine Enthusiast. Available at:
<https://www.winemag.com/2018/05/01/cool-vs-warm-climate-wine/> [Accessed 24
April 2022].
o

Explains how aging of the wine changes the flavour characteristics.
Article that explains the change of colour in wine after aging.
Shahorin, W., 2021. How does carbon dioxide affect titration?. [online]
Everythingwhat.com. Available at: <https://everythingwhat.com/how-does-carbondioxide-affect-titration> [Accessed 23 April 2022].
o
Website that details how carbon dioxide affects titration with NaOH as it
weakens the base, and turn solutions more acidic when reacted with water.

Shankar, V., Mahboob, S., Al-Ghanim, K., Ahmed, Z., Al-Mulhm, N. and Govindarajan, M.,
2021. A review on microbial degradation of drinks and infectious diseases: A
perspective of human well-being and capabilities. Journal of King Saud University Science, [online] 33(2), p.101293. Available at:
<https://www.sciencedirect.com/science/article/pii/S1018364720304067> [Accessed
23 April 2022].
o

The Australian Wine Research Institute. n.d. Acidity and pH - The Australian Wine
Research Institute. [online] Available at:
<https://www.awri.com.au/industry_support/winemaking_resources/frequently_asked
_questions/acidity_and_ph/#:~:text=Precipitation%20of%20potassium%20bitartrate%
20is,titratable%20acidity%20(TA)%20decreases.> [Accessed 23 April 2022].
o

Website that explains what terrior are and its relevance to wine.
Walter-Peterson, H., 2013. How Soil pH Influences Grapes. [online] Growingproduce.com.
Available at: <https://www.growingproduce.com/fruits/commentary-how-soil-phinfluences-grapes/> [Accessed 23 April 2022].
o

Report that goes further into detail the difference between pH and titratable
acidity. This being the ability to measure the ability of hydrogen ions to
disassociate and the concentration of disassociated hydrogen ions.
VinePair. n.d. Learn About Terroir | Understanding Terroir | Wine 101. [online] Available
at: <https://vinepair.com/wine-101/terroir-wine-guide/> [Accessed 26 April 2022].
o

Explains the difference between pH and titratable acidity when measuring acids
in alcohol.
Tyl, C. and Sadler, G., 2017. pH and Titratable Acidity. 1st ed. [ebook] Cham: © 2017
Springer International Publishing, pp.389 - 406. Available at:
<https://link.springer.com/chapter/10.1007/978-3-319-45776-5_22#citeas>
[Accessed 25 April 2022].
o

Report that explains the perfect conditions to prohibit microbial and pathogen
growth, being a combination of low pH and weak TA.
Details how the pH of soil affects the acid to sugar ratio within ripening grapes.
Winfieldunited.com. 2015. Pesticide Performance and pH Levels. [online] Available at:
<https://www.winfieldunited.com/news-and-insights/pesticide-performance-and-phlevels> [Accessed 24 April 2022].
o
Gives an understanding of the pH of majority of pesticides. This then influences
the acidity within the growing grapes.