Wine analysis

Aerial Taint

Over the last decade or so, much progress has been made on eradicating taint in the closure and packaging industry. The cork industry has cleaned up its act considerably; this, coupled with the development of alternative closures means that wine, once packaged, is less likely to become contaminated. However, one are that has been seriously overlooked is atmospheric or aerial taint in wineries, warehouses and cellars.

Up until recently, it had not been possible to quantify traces of complex molecules in the atmosphere. However, we have developed a new technique in order to make quantitation of aerial taint possible. This quantitation covers all the potential anisoles (see Haloanisole Screen) and chlorophenols, which are the precursors of the anisoles.

If you would like us to work with you to investigate and solve aerial taint problems, please contact the team to discuss how this method can help you.

Acetaldehyde

Acetaldehyde analysis can be used as way to indicate problems: acetaldehyde may be present at high concentrations if the fermentation is ‘stuck’, or wine has been stored in air (and oxidised) or when there is a problem with microbiological contamination.
Method: Gas chromatography.
Amount to send: 100ml.

Alcohol

Alcoholic strength analysis is carried out by two methods, depending on the type of sample and the purpose of the analysis:

Determination by distillation: this method is used for resolving legal problems such as labelling issues.
Amount to send: 300ml.

Determination by FTIR: this rapid method has been developed at Campden BRI using a FOSS Winescan. It is suitable for most wines/fortified wines and is accurate to ± 0.1g/litre.
Amount to send: 100ml.

Benzoic acid

Benzoic acid is a permitted preservative in flavoured alcoholic beverages (alcopops). However, manufacturers are advised to check that the levels of benzoic acid present are not above the legal limit of 150mg/litre.
Method: HPLC.
Amount to send: 200ml.

'Brett' or 4–ethyl phenol

Over the last few years, the term Brett' has been increasingly quoted in the trade. Brett, or to be more precise, spoilage of wine due to the presence of by–products of that contaminant yeast Brettanomyces, is a controversial subject. The most common chemical indicated in Brett spoilage is 4–ethyl phenol. Campden BRI is now able to quantify this chemical and deliver precise science into what has previously been a subjective issue. The analysis is carried out by gas chromatography.
Method: GC.
Amount to send: 1 sealed unopened bottle.

Calcium

Metals (calcium, copper, iron, zinc, silver, lead, magnesium, potassium, sodium)

Some metals, in particular copper and iron, can lead to haze formation in bottled wine. It is therefore recommended that winemakers screen for these metals prior to bottling. In addition, due to the increased use of copper sulphate as a fining agent and the growth in organic viticulture, copper levels in wine are rising worldwide.

For the heavy metal lead, wines can be screened for compliance with the legal limit of 0.1mg/litre.
Amount to send: 250ml for any number of metals.

Calorific value

The calorific value of wine is calculated based on the levels of the two main energy-containing components in wine: alcohol and carbohydrates.
Method: HPLC and distillation
Amount to send: 300ml.

Carbon dioxide

Winemakers may wish to check whether the levels of carbon dioxide in the wine are correct for the style of wine being made. Winemakers may occasionally consider it necessary to add carbon dioxide to 'liven up' their wine, in which case carbon dioxide testing before carbon dioxide addition is essential to decide the correct dosing level. In some cases, abnormally high levels of carbon dioxide can be indicative of spoilage.
Method: Corning carbon dioxide meter
Amount to send: A sealed bottle. If microbiology is also required, please send 2 sealed bottles.

Chill stability

Chill stability is one of the tests that we recommend winemakers consider in order to avoid ‘tartrate’ crystals forming in bottles rendering the wine non–commercial. Ideally, this analysis should be carried out pre–bottling but it may also be carried out post bottling. If instability is detected, our experts can make recommendations and assist you with resolving this problem.
Method: –4 °C for 72 hours.
Amount to send: 200ml.

Contents

We can provide a volume check for those using bottles that have a minimum fill level. Generally we recommend that a statistical sample is taken to reduce the risk of compliance failure. You may wish to discuss with us in advance the sampling procedure.
Method: Calibrated cylinder.
Amount to send: full unopened bottles.

Copper

The addition of copper sulphate pentahydrate is used to remove bad tastes or odours in wine due to the presence of sulphur compounds such as hydrogen sulphide. It is essential to ensure that the copper levels are below the recommended maximum of 0.5mg/litre, above which haze problems can occur.
Methods: copper is determined by atomic absorption
Amount to send: 250ml for any number of metals

Density

Density can be used as a quick check for homogeneity or consistency in finished spirits.
Method: Digital density meter
Amount to send: 100ml

Discolouration:'browning' or 'pinking'

White wines have the potential to discolour on storage, and failure to check susceptibility to discoloration pre-bottling or pre-shipment can be an expensive mistake. If wines are found to be susceptible, the winemaker can rectify the situation with fining.
Method: we use standard methods of acid-induced browning with colour comparison.
Amount to send: 200ml

4-ethylphenol

Over the last few years, the term Brett' has been increasingly quoted in the trade. Brett, or to be more precise, spoilage of wine due to the presence of by–products of that contaminant yeast Brettanomyces, is a controversial subject. The most common chemical indicated in Brett spoilage is 4–ethyl phenol. Campden BRI is now able to quantify this chemical and deliver precise science into what has previously been a subjective issue. The analysis is carried out by gas chromatography.
Method: GC.
Amount to send: 1 sealed unopened bottle.

Ethanol

Over the last few years, the term Brett' has been increasingly quoted in the trade. Brett, or to be more precise, spoilage of wine due to the presence of by–products of that contaminant yeast Brettanomyces, is a controversial subject. The most common chemical indicated in Brett spoilage is 4–ethyl phenol. Campden BRI is now able to quantify this chemical and deliver precise science into what has previously been a subjective issue. The analysis is carried out by gas chromatography.
Method: GC.
Amount to send: 1 sealed unopened bottle.

Ethyl carbamate

Ethyl carbamate, a suspected mild carcinogen, is formed naturally in wine by the reaction of urea with ethanol. This reaction is favoured with long storage times, warmer temperatures, or when higher levels of ethanol and urea are present. Fortified wines are at a particular risk of ethyl carbamate formation.

Some countries have recommended limits on ethyl carbamate. Indicative values are:

• Table wine: 30 ppb
• Fortified wines: 100 ppb
• Spirits: 150 ppb
• Fruit spirits: 400 ppb

Method: This analysis is carried out by gas chromatography–mass spectrometry
Amount to send: fully sealed unopened bottle.

Extraction force

Extraction Force (EF), measured in decaNewtons, is the force required to extract a closure from a bottle. This is an important parameter for many reasons. Obtaining the EF value can help in evaluating the following:

• a) A high EF value will indicate that the closure is too difficult to extract from the bottle. This may result in dissatisfied customers at best and at worst may lead to a broken bottle.
• b) A low EF value will indicate that the closure is too loose in the bottle, leading to wine leakage and premature oxidation.
• c) Comparison of EF values may assist in predictive variation in wine quality.

Method: in house manual meter.
Amount to send: fully sealed unopened bottle.

Filterability

Testing filterability will provide winemakers with a measure of how well the wine will perform in the final filtration before bottling. If the filterability is poor, the winemaker will have the chance to apply palliative treatments, ensuring homogeneity and avoiding problems during bottling.
Method: Wine is passed through a standard 0.65 micron cellulose membrane and filtration speed monitored.
Amount to send: 300ml.

Total and free sulphur dioxide: Free SO₂

Sulphur dioxide (SO₂) is used as an antioxidant and preservative and has become widely used in winemaking. If it is carefully adjusted prebottling, with attention being paid to the pH and type of wine, the winemaker can ensure that the quality of wine will be preserved on storage.

The EU has set a legal limit for total SO2 of 150mg/litre in red wines and 200mg/litre in white wines. However, because some individuals are sensitive to SO2, it is mandatory to include ‘contains sulphites’ on the label if total SO₂ is over 10mg/litre.

‘Free’ SO2 is that which is unbound to compounds in the wine and is therefore able to exert an antioxidant/preservative action. ‘Bound’ SO₂ is that which has already been complexed to other compounds in the wine (such as sugars) and has essentially been quenched such that it no longer has antioxidant/preservative activity. Total SO₂, is the sum of both of these forms.

Method: Free and total SO2 are determined by either the manual aspiration method or by using the Foss FIASTAR (flow injection analysis).
Amount to send: at least 200ml in full well sealed bottles.

Fructose

Fructose is a natural form of sugar found in fruits and, along with glucose, is the main form of sugar found in grapes. The amounts of fructose + glucose will define whether the wine is sweet or dry and will also be indicative of the progress of the fermentation process. Typically the ratio of glucose: fructose will be 1:1, and ratios outside of this range can be indicative of either tampering or microbial contamination.
Method: Fructose and glucose are measured by HPLC.
Amount to send: 50–100ml.

Fusel oils

Fusel oils, or higher alcohols and esters, can give spirit and liqueur makers a measure of the quality of their product – higher levels indicating a better quality product. This test can also be used an indicator of fraudulent practices.
Method: Gas chromatography.
Amount to send: 100ml in well sealed bottle.

Glucose: Reducing sugars

Fructose is a natural form of sugar found in fruits and, along with glucose, is the main form of sugar found in grapes. The amounts of fructose + glucose will define whether the wine is sweet or dry and will also be indicative of the progress of the fermentation process. Typically the ratio of glucose: fructose will be 1:1, and ratios outside of this range can be indicative of either tampering or microbial contamination.
Method: Fructose and glucose are measured by HPLC.
Amount to send: 50–100ml.

Glycerol

Glycerol is formed naturally in wine as a product of fermentation. Levels of glycerol in wine will vary according to factors such as the ripeness of the grapes, pH, fermentation conditions as well as the yeast strain. Many winemakers believe that glycerol can enhance the taste of the wine, and may contribute to its texture or mouth–feel. Typical levels in dry wines range from 4–10 g/litre, but levels up to 20g/litre have been recorded.
Method: HPLC analysis.
Amount to send: 50ml.

Glycol: (ethylene–glycol and propylene–glycol)

Ethylene and propylene glycols, widely used as refrigeration elements used to control temperature of must and juice. In its pure form, it is an odorless, colorless, syrupy liquid with a sweet taste. Ethylene glycol is toxic. Accidental contamination of juice, must or wine could occur and therefore could affect large quantities of wine. Propylene glycol can also be used as an additive to increase body and smoothness of the wine.
Method: GC–MS.
Amount to send: min 50ml.

Gravity: Density

Density can be used as a quick check for homogeneity or consistency in finished spirits.
Method: Digital density meter.
Amount to send: 100ml.

Haloanisole screen

We can offer a full haloanisole screen which covers:

• 2–Bromoanisole
• 2–Chloroanisole
• 4–Bromoanisole
• 4–Chloroanisole
• 2,4–Dibromoanisole
• 2,4–Dichloroanisole
• 2,6–Dichloroanisole
• 2,4,6–Tribromoanisole
• 2,4,6–Trichloroanisole
• 2,3,4,5–Tetrachoroanisole
• Pentachloroanisole

Method: SPME with GCMS.
Amount to send: a sealed unopened bottle.

Halophenol Screen

We can offer a full Halophenol screen which covers:

• 2–Bromophenol
• 2–Chlorophenol
• 4–Bromophenol
• 2,4–Dibromophenol
• 2,6–Dibromophenol
• 2,4–Dichlorophenol
• 2,6–Dichlorophenol
• 2,4,6–Tribromophenol
• 2,4,6–Trichlorophenol
• 2,3,4,6–Tetrachlorophenol

Method: SPME with GCMS.
Amount to send: a sealed unopened bottle.

Heat stability: Protein/Heat stability

Hazes in wine may be caused by several factors, and protein instability is one of these. Proteins in wines are derived from the grapes and so levels will be affected by grape variety, pH, how the wine is processed and the condition of the fruit: thus protein levels vary widely in wines. Protein haze formation is a complex process, as it is dependent upon both protein content as well as interactions of these proteins with phenolic components. Therefore, due to the complexity of this haze–forming process, prediction of protein instability is best carried out via a functional test. Our method involves heating, and visual assessment of haze by one of our analytical experts.

Protein instability is one of the analysis that we recommend pre–bottling, since it allows winemakers to apply palliative measures to correct any potential problems.
Amount to send: 100ml.

Hydrogen Sulphide (H₂S)

Screwcap closures are becoming increasingly popular in the market place. This means of sealing wine bottles has many advantages over alternative closures. However, it is becoming increasingly apparent that unless a wine is scrupulously selected and treated prior to bottling, reductive odours, including those caused by the presence of hydrogen sulphide (H₂S), can become obvious, rendering the wine unfit for sale.

Although reductive odours can form in wines sealed with closures other than screwcaps, for a variety of reasons, this type of problem is more frequently encountered where screwcaps are used.

We recommend that H₂S analysis be used as a key indicator of reductive taint and that this compound is analysed as a quality control parameter. Further evaluation of reductive odours would only be necessary if re–selection and treatment prior to bottling did not resolve the problem.
Method: H2S is quantitated with a dedicated GC with a specific detector.
Amount to send: Sealed unopened bottle.

Iron

At high concentrations, the presence of iron can increase the risk of forming an iron casse (haze). Winemakers, if aware of this problem, can use a variety of methods to correct it e.g. addition of gum Arabic, citric acid or tannin. Again, we recommend that this analysis is carried out pre–bottling so that the winemaker can apply palliative treatments and avoid the expense of the wine being rejected.
Amount to send: 250ml for any number of metals.

Lead

Metals (calcium, copper, iron, zinc, silver, lead, magnesium, potassium, sodium).

Some metals, in particular copper and iron, can lead to haze formation in bottled wine. It is therefore recommended that winemakers screen for these metals prior to bottling. In addition, due to the increased use of copper sulphate as a fining agent and the growth in organic viticulture, copper levels in wine are rising worldwide.

For the heavy metal lead, wines can be screened for compliance with the legal limit of 0.1mg/litre.
Amount to send: 250ml for any number of metals.

Mercaptans/ Reductive screen

The term reduction is used to describe a taint in a wine caused by volatile sulphur compounds the main one of concern being mercaptans. Mercaptans is such a big problem because it is particularly pungent causing cabbagey or burnt rubber offer odors. It is formed from Hydrogen sulphide which is sometimes produced by yeast during fermentation if the yeast has access to a sulphur–containing nitrogen source.
Method: GC with specific detectors.
Amount to send: 1 sealed unopened bottle.

Magnesium

Metals (calcium, copper, iron, zinc, silver, lead, magnesium, potassium, sodium)

Some metals, in particular copper and iron, can lead to haze formation in bottled wine. It is therefore recommended that winemakers screen for these metals prior to bottling. In addition, due to the increased use of copper sulphate as a fining agent and the growth in organic viticulture, copper levels in wine are rising worldwide.

For the heavy metal lead, wines can be screened for compliance with the legal limit of 0.1mg/litre.
Amount to send: 250ml for any number of metals.

Malic acid

The progress of malolactic fermentation can simply be checked by measuring the levels of malic acids.
Method: enzymatic analysis
Amount to send: 200ml.

Methanol

Methanol is formed in wines by the action of natural grape enzymes on the pectin present in the fruit. Red wines tend to have higher concentrations than white wines due to the extended maceration time with skins. Fruit spirits, distilled spirits and fortified wines also contain methanol. Due to the toxicity of methanol, legal limits have been set for all these types of alcoholic beverages, and we will advise you if analysis reveals that your product is not compliant.
Method: Gas chromatography.
Amount to send: 100ml secure sealed bottle.

Microscopic examination

Our experts are able to conduct a microscopic contamination to help to determine the identity of foreign bodies in wine e.g. are particles glass, microbial, crystalline or some form of haze?

This is a specialist analysis and customers are advised to discuss the problem with our staff prior to sending their sample.
Amount to send: We will need to advise you on a case–by–case basis.

Price and turnaround time: On application. This is one of our troubleshooting activities and we ask that you please call our experts to discuss the problem.

Microbiology

Our experts are able to conduct a microscopic contamination to help to determine the identity of foreign bodies in wine e.g. are particles glass, microbial, crystalline or some form of haze?

This is a specialist analysis and customers are advised to discuss the problem with our staff prior to sending their sample.
Amount to send: We will need to advise you on a case–by–case basis.

Price and turnaround time: On application. This is one of our troubleshooting activities and we ask that you please call our experts to discuss the problem.

Naphthalene

Naphthalene can be absorbed into wine from the environment materials such as fiberglass and resins contain naphthalene spills of oils or solvents can also be a source. It can cause a moth ball odour in the wine or simply a musty taint.
Method: GCMSMS.
Amount to send: 1 sealed unopened bottle.

Natamycin

Method: LCMS
Amount to send: 1 sealed unopened bottle.

Ochratoxin A (OTA)

Ochratoxin A (often abbreviated to OTA) is a potent toxin produced by some fungal species that infect crops, including vines. OTA has been reported in wines, and many wineries, supermarkets and bottlers are monitoring levels in their products.
Method: OTA is measured using extraction methods that are specific for OTA (immunoaffinity columns) and quantitation by HPLC.
Amount to send: 500ml.

Optical density

Measurement of optical density at diagnostic wavelengths can give wine makers an indication of their wine's colour based on its content of anthocyanins and polyphenols.
Method: Optical density is determined with a spectrophotometer.
Amount to send: 100ml.

Organic Acids

A new Liquid Chromatography–Mass Spectrometry (LC–MS) method, with high sensitivity and selectivity, has been developed for the analysis of a range of organic acids in beverages.

The method can analyse for malic, tartaric, lactic, succinic, citric, benzoic and ascorbic acid and has been designed to take into account the differing levels of acid found in most drinks. The new service provides greater selectivity by isolating characteristic signals unique to each acid reducing the possibility of incorrect assignment from other acids or interfering background components. All acids can be detected down to 0.2ppm.

We will be complementing this LC–MS suite of analysis with the addition of Ion Chromatography analyses for acetic, formic and oxalic acid.
Method:LC–MS/ Ion Chromatography.
Amount to send: 100ml.

Over Pressure

Measurement of over pressure in a bottle will provide a check that a wine is sufficiently carbonated to be considered ‘sparkling’ and also warn the winemaker if the pressure is too high and there is risk of bottle breakage.
Method: calibrated aphrometer.
Amount to send: Fully sealed unopened bottle.

Pesticide screen

Assessing legal compliance is a key way to avoid product recalls and brand damage. At Campden BRI, we offer a full pesticide screen to ensure that your products meet legal specifications.

Pesticides covered in this screen include:

• Organochlorine analytes
• Organophosphates
• Carbamates
• Synthetic pyrethroids

Several other miscellaneous analytes are also included in this screen. For full details please do not hesitate to contact the Campden BRI team.
Amount to send: 1 Sealed unopened bottle.

pH (general acidity)

Method: pH is measured by electrode and FTIR Winescan.
Amount to send: 50-100ml.

Phenolics (total)

Measurement of the phenolics in wine will give an indication of the bitter/astringent flavours. Phenolics will vary according to grape variety, but also can be high if a wine has been over– pressed.
Method: Reaction with Folin–Ciocalteu's phenol reagent and optical absorbance measurement.
Amount to send: 500ml.

Potassium

Metals (calcium, copper, iron, zinc, silver, lead, magnesium, potassium, sodium)

Some metals, in particular copper and iron, can lead to haze formation in bottled wine. It is therefore recommended that winemakers screen for these metals prior to bottling. In addition, due to the increased use of copper sulphate as a fining agent and the growth in organic viticulture, copper levels in wine are rising worldwide.

For the heavy metal lead, wines can be screened for compliance with the legal limit of 0.1mg/litre.
Amount to send: 250ml for any number of metals.

Potential alcohol (total)

Measurement of the sugar in grape juice will give an indication of the potential amount of alcohol that could be produced were fermentation to go to completion. The sugar content of grapes will vary by variety as well as by growth conditions for the harvest year; therefore wine makers may wish to make an assessment of the potential alcohol of their juice before fermentation. Potential alcohol can also to measure post fermentation for legislative reasons.
Potential alcohol is calculated from the total amount of sugar present (Glucose,Fructose and Sucrose).
Amount to send: 250ml.

Pre and Post shipment packages

Pre and Post Shipment analysis is a cost effective way to anticipate problems and solve them in the tank or vat - rather than being left with unsaleable wine in bottles. Our analysis suite, combined with our expert knowledge, allows you to optimise shelf life and quality at point of sale, ensure that wine is compliant with legal regulations and prevent financially damaging quality issues arising.

Pre-shipment Analysis
The analyses included in this suite typically include:

• Alcohol
• Free sulphur dioxide
• Total sulphur dioxide
• Volatile acidity
• Chill stability
• Total acid
• pH
• Protein stability
• Discolouration(in white wines only)
• Filtration index (in rose and red wines only)
• Organoleptic assessment

* All wines are tasted by an experienced panel, trained to detect and identify taints and contaminants. Combined with data from the above suite of tests, we can then use our experience to advise you on the quality, acceptability and legality of your product and advise you of palliative treatments if problems arise.

Example of a Pre-shipment certificate of analysis (pdf).

Post-shipment Analysis:

• Microbiology
• Alcohol
• Free sulphur dioxide
• Total sulphur dioxide
• Total acid
• Volatile acid
• pH
• Reducing sugar
• Copper
• Iron
• Protein stability
• Chill stability
• Discolouration(in white wines only)
• Filtration index (in rose and red wines only)
• Organoleptic assessment*

* All wines are tasted by an experienced panel, trained to detect and identify taints and contaminants. Combined with data from the above suite of tests, we can then use our experience to advise you on the quality, acceptability and legality of your product and advise you of palliative treatments if problems arise.

Example of a Post-shipment certificate of analysis (pdf).

Protein/heat stability

Hazes in wine may be caused by several factors, and protein instability is one of these. Proteins in wines are derived from the grapes and so levels will be affected by grape variety, pH, how the wine is processed and the condition of the fruit: thus protein levels vary widely in wines. Protein haze formation is a complex process, as it is dependent upon both protein content as well as interactions of these proteins with phenolic components. Therefore, due to the complexity of this haze–forming process, prediction of protein instability is best carried out via a functional test. Our method involves heating, and visual assessment of haze by one of our analytical experts.

Protein instability is one of the analysis that we recommend pre–bottling, since it allows winemakers to apply palliative measures to correct any potential problems.
Amount to send: 100ml.

Silver

Metals (calcium, copper, iron, zinc, silver, lead, magnesium, potassium, sodium)

Some metals, in particular copper and iron, can lead to haze formation in bottled wine. It is therefore recommended that winemakers screen for these metals prior to bottling. In addition, due to the increased use of copper sulphate as a fining agent and the growth in organic viticulture, copper levels in wine are rising worldwide.

For the heavy metal lead, wines can be screened for compliance with the legal limit of 0.1mg/litre.
Amount to send: 250ml for any number of metals.

Sodium

Metals (calcium, copper, iron, zinc, silver, lead, magnesium, potassium, sodium)

Some metals, in particular copper and iron, can lead to haze formation in bottled wine. It is therefore recommended that winemakers screen for these metals prior to bottling. In addition, due to the increased use of copper sulphate as a fining agent and the growth in organic viticulture, copper levels in wine are rising worldwide.

For the heavy metal lead, wines can be screened for compliance with the legal limit of 0.1mg/litre.
Amount to send: 250ml for any number of metals.

Sorbic Acid

Sorbic acid acts as an antifungal agent and will limit the growth of yeast and fungi. Sorbic acid is permitted in wine up to a legal maximum of 200mg/litre although high levels of sorbic acid can lead to a geranyl taint on wine. Sorbic acid is also used as a preservative in flavoured alcoholic beverages.
Method: HPLC
Amount to send: 100ml.

Reducing sugars

Fructose is a natural form of sugar found in fruits and, along with glucose, is the main form of sugar found in grapes. The amounts of fructose + glucose will define whether the wine is sweet or dry and will also be indicative of the progress of the fermentation process. Typically the ratio of glucose: fructose will be 1:1, and ratios outside of this range can be indicative of either tampering or microbial contamination.
Method: Fructose and glucose are measured by HPLC.
Amount to send: 50–100ml.

Sugar (total)

Total sugar is calculated based on the amounts of glucose,fructose and sucrose in the wine. Sucrose is not present naturally in wines, and so its presence is indicative of fraudulent practice. We can measure sucrose in wine by HPLC.
Method: HPLC.
Amount to send: 100ml.

Sugar free dry extract

Sugar free dry extract is a measure of everything in the wine except sugars, water, ethanol and acid and is essentially a reflection of the amount of minerals and trace elements. This value is calculated based on the density, alcohol and sugar content of the wine.
Amount to send: 250ml.

Note: Sugar free dry extract will be provided free of charge if alcohol, sugar content and density analysis have also been ordered. Please request the analysis ‘sugar free dry extract’, you will not be charged any extra for requesting it.

Sulphur dioxide (SO₂) total and free

Total and free sulphur dioxide Sulphur dioxide (SO₂) is used as an antioxidant and preservative and has become widely used in wine making. If it is carefully adjusted prebottling, with attention being paid to the pH and type of wine, the winemaker can ensure that the quality of wine will be preserved on storage.

The EU has set a legal limit for total SO₂ of 150mg/litre in red wines and 200mg/litre in white wines. However, because some individuals are sensitive to SO₂, it is mandatory to include ‘contains sulphites’ on the label if total SO₂ is over 10mg/litre.

‘Free’ SO₂ is that which is unbound to compounds in the wine and is therefore able to exert an antioxidant/preservative action. ‘Bound’ SO₂ is that which has already been complexed to other compounds in the wine (such as sugars) and has essentially been quenched such that it no longer has antioxidant/preservative activity. Total SO₂, is the sum of both of these forms.

Method: Free and total SO₂ are determined by either the manual aspiration method or by using the Foss FIASTAR (flow injection analysis).
Amount to send: at least 200ml in full well sealed bottles.

Tasting

Our expert tasters will make a general assessment on the quality and the commercial acceptability of wines, and provide a descriptive summary of the characteristics of the wine. In addition, parameters such as the batch number, type of closure or size of the container will be considered to give an overall assessment on shelf life.

Our tasting services also offer difference tests, which are conducted with a panel of accredited tasters in our sensory suite. These tests are conducted under standardised conditions, using isolated booths with dark, coded glasses and data are recorded via our Compusense system. In the triangular test, tasters receive three glasses: two contain product A, one contains a product B. The tasters are asked to identify product B (i.e. the odd one out). Triangle tests are therefore useful as a very sensitive tool to check for significant differences between wines, such as differences between batches, or for the influence of different storage conditions.
Amount to send: Tasting 1 bottle; difference testing and fault identification, 2 bottles of each product.

Taint identification

Taint or alleged taint is probably one of the most contentious subjects in the trade. Taint can arise from a plethora of sources, such as inadequately cleaned vats, tainted wood, cleaning fluids, closures, dirty bottles, proximity to odourous substances etc., or it may simply be a filtration issue or due to batch variation. This list can go on ad infinitum.

For comprehensive taint investigation, it is imperative to have access to a range of technical services.

Sophisticated analysis in our high tech lab ( GCMSMS, LCMSMS), we are able to analyse for:

• All the anisoles ( including TCA) implicated in musty taint
• Brettanomyces ( Brett)
• Naphthalene
• Natamycin
• Reductive compounds including mercaptans
• GCMS profiling with computational overlaying comparing fingerprints

We also use a wide range of sensorial techniques such as Radar diagrams, Triangle tests, Benchmarking

Also crucial to any taint investigation is our extensive knowledge of wine production, bottling and storage procedures.

We have also recently developed a method to measure aerial taints.

Titratable acid

Titratable acid (TA) provides a measure of the acidity of the wine. TA is related to the wine's ‘tart’, which provides balance for the residual sugars and ethanol in the wine.
Method: Manual titration against a standard base.
Amount to send: 100ml.

Torque inch pounds

We can measure the amount of torque required to open a screw cap closure. This information can be used to determine whether the closure performs according to specifications.
Amount to send: Fully sealed unopened bottles.

Total dry extract

The total dry extract is a measure of everything in the wine except water and alcohol. A high dry extract value is believed to give the wine a fuller body and greater amount of flavour, and should ideally be in balance with the alcohol, acidity and sugar levels in a wine. Total dry extract is calculated based on the alcohol content and density of the wine.
Amount to send: 250ml.

Note: Total dry extract will be provided free of charge if alcohol content and density analysis has been ordered. Please request the analysis Total dry extract but you will not be charged any extra for requesting it.

Total phenolics

Measurement of the phenolics in wine will give an indication of the bitter/astringent flavours. Phenolics will vary according to grape variety, but also can be high if a wine has been over–pressed.
Method: Reaction with Folin–Ciocalteu's phenol reagent and optical absorbance measurement.
Amount to send: 500ml.

Total potential alcohol

Measurement of the sugar in grape juice will give an indication of the potential amount of alcohol that could be produced were fermentation to go to completion. The sugar content of grapes will vary by variety as well as by growth conditions for the harvest year; therefore wine makers may wish to make an assessment of the potential alcohol of their juice before fermentation. Potential alcohol can also to measure post fermentation for legislative reasons.

Potential alcohol is calculated from the total amount of sugar present (Glucose,Fructose and Sucrose)
Amount to send: 250ml.

Total SO₂

Sulphur dioxide (SO₂) is used as an antioxidant and preservative and has become widely used in winemaking. If it is carefully adjusted prebottling,with attention being paid to the pH and type of wine, the winemaker can ensure that the quality of wine will be preserved on storage.

The EU has set a legal limit for total SO₂ of 150mg/litre in red wines and 200mg/litre in white wines. However, because some individuals are sensitive to SO₂, it is mandatory to include ‘contains sulphites’ on the label if total SO₂ is over 10mg/litre.

‘Free’ SO₂ is that which is unbound to compounds in the wine and is therefore able to exert an antioxidant/preservative action. ‘Bound’ SO₂ is that which has already been complexed to other compounds in the wine (such as sugars) and has essentially been quenched such that it no longer has antioxidant/preservative activity. Total SO₂, is the sum of both of these forms.

Method: Free and total SO₂are determined by either the manual aspiration method or by using the Foss FIASTAR (flow injectionanalysis).
Amount to send: at least 200ml in full well sealed bottles.

Total sugar

Total sugar is calculated based on the amounts of glucose,fructose and sucrose in the wine. Sucrose is not present naturally in wines, and so its presence is indicative of fraudulent practice. We can measure sucrose in wine by HPLC.
Method: HPLC.
Amount to send: 100ml.

Tri-chloro and Tri-bromo anisole (TCA and TBA)

TCA and TBA are compounds from the haloanisole group. They are derived by the biodegradation of halophenols commonly found in cork and wineries from the use of bleach, sanitisers and wood presevatives. The conversion of phenols to anisoles and with the migration of these into the wine results in ‘cork taint’.

We are also able to offer a full haloanisole screen.

Method: SPME coupled with GC–MS.
Amount to send: Fully sealed unopened bottle.

Volatile acid

Volatile acidity (VA) refers to the acids present in wine that are steam volatile, and are mainly composed of acetic acid with traces of other volatile organics acids (e.g. butyric, propionic). Acetic acid does not occur naturally in grapes, but is formed instead during the wine making process by either the metabolism of bacteria or by the chemical oxidation of alcohol. Therefore VA is usually viewed as a measure of spoilage, and winemakers should monitor levels through the wine making process, pre–bottling and post bottling. Although small amounts of VA are believed to ‘lift’ the aroma of wine and add complexity to the flavour, winemakers should also be aware of legal limits for VA.
Method: Distillation and manual titration.
Amount to send: 100ml.

Zinc

Metals (calcium, copper, iron, zinc, silver, lead, magnesium, potassium, sodium).

Some metals, in particular copper and iron, can lead to haze formation in bottled wine. It is therefore recommended that winemakers screen for these metals prior to bottling. In addition, due to the increased use of copper sulphate as a fining agent and the growth in organic viticulture, copper levels in wine are rising worldwide.

For the heavy metal lead, wines can be screened for compliance with the legal limit of 0.1mg/litre.
Amount to send: 250ml for any number of metals.