Mar
2013
Proper maintenance of quartz cuvettes is an essential part of spectrophotometric analysis.
The following notes are based on the recommendations of Australian Standard AS 3753-2001.
Cuvettes in regular use should be stored either:
a) in a box lined with a suitably soft material (possibly one supplied by the manufacturer);
b) immersed in distilled water;
c) immersed in 1% v/v nitric acid.
Before use, cuvettes should be cleaned to remove any accumulated residue.
If the cuvettes appear clean, simply rinse several times with distilled water, then once with acetone (to prevent watermarks) and leave to air-dry in an inverted position (eg...
Continue reading Care and Handling of Cuvettes
Jan
2013
Click here to Download the Survey of Yeast Assimilable Nitrogen Status in Chardonnay and Shiraz Grapes from the Granite Belt 2012 Vintage as a PDF
Continue reading Survey of Yeast Assimilable Nitrogen Status in Chardonnay and Shiraz Grapes from the Granite Belt 2012 Vintage
Nov
2012
DO YOU KNOW THE QUALITY OF YOUR IRRIGATION WATER
Water quality guidelines recommended for irrigation and general on-farm and domestic use have been developed by the Primary Industries and Natural Resource Management Ministerial Counicils.
The guidelines cover several water parameters that should be analysed to ensure your water is suitable for its intended use. At Vintessential, we have packaged the major parameters into a convienient and cost effective Irrigation Water Test Suite. This suite of tests will give you an overview of the qualitiy of your water and identify any issues that may be affecting water quality.
The Irrigation Water Test Suite is...
Continue reading Irrigation Water Analysis
Nov
2012
Petiole testing can provide a snapshot of the nutrient status of the vine. Obtaining quantitative information on nutrient levels can assist in determining the effectiveness of fertiliser applications and also help identify the cause of any specific vine problems.
The following table outlines nutrient guidelines for the full list of parameters tested in our Petiole Analysis Suite.
|
Nutrient |
Deficient |
Marginal |
Adequate |
High |
Toxic |
|
Nitrogen (%) |
|
|
0.80-1.10 |
|
|
|
Nitrate Nitrogen (%) |
<340 |
340-499 |
500-1200 |
>1200 |
|
|
Phosphorous (%) |
<0.15 |
0.15-0.24 |
0.25-0.50 |
>0.50 |
|
|
Potassium (%) |
<1.0 |
1.0-1.7 |
1.8-3.0 |
|
|
|
Calcium (%) |
|
|
1.2-2.5 |
|
|
|
Magnesium (%) |
<0.30 |
0.30-0.39 |
>0.40 |
|
|
|
Sodium (%) |
|
|
0.10-0.30 |
0.40-0.50 |
>0.50 |
|
Chloride (%) |
|
|
<1.0 |
1.0-1.5 |
>1.0 or 1.5 |
|
ZInc (mg/kg) |
<15 |
15-26 |
>26 |
|
|
|
Manganese (mg/kg) |
<20 |
20-29 |
30-60 |
|
>500 |
|
Iron (mg/kg) |
|
7 |
70 |
|
|
|
Copper (mg/kg) |
<3 |
3.6 |
>6 |
|
|
|
Boron (mg/kg) |
<25 |
26-30 |
30-100 |
|
>100 |
From Iland et al, 2011: The Grapevine from the science to the practice of growing vines for wine. Patrick Iland Wine Promotions Pty Ltd.
Result...
Continue reading Grapevine Petiole Analysis
Aug
2012
From 1 July 2012, new allergen labelling requirements came into effect in the European Union (EU).
If milk (casein) or egg products have been used and the wine has not tested negative for these residues using a technique with a detection limit of 0.25mg/L, then the presence of allergens must be indicated on the label.
Vintessential has recently introduced Allergen Analyses to our range of Chemical Wine Tests. These methods screen for the presence of milk and egg residues in wine, using ELISA based methods with detection limits below 0.25mg/L.
The cost of this analysis per sample is:
Continue reading Allergen Residue Analysis
Aug
2012
Measuring pH is one of the most important tests in the winery but it can also be one of the most frustrating. A sluggish or non-reproducible response indicates that the pH reading may not be accurate. Can you trust the equipment you’re using?
Taking a few simple steps to look after the electrode each time you use it and before putting it away for longer term storage, can help maximize its life and save money.
The best practice for each model of electrode varies so follow manufacturer’s instructions first. If in doubt, the following guidelines should help prevent problems occurring:
Continue reading Take care of your pH electrode!
Apr
2012
To avoid spoilage characters and hours of work on starter cultures in the cold days ahead, it is important to acknowledge sluggish ferments early and act quickly with the appropriate rescue yeast.
Rescue yeast
Fermichamp has the specific ability to metabolise fructose (the dominant sugar found in most stuck ferments) in high alcohol conditions. Early intervention on ferments that are slowing and at risk of becoming stuck can produce results with very little negative impact and save extra effort if intervention is left too late.
Fermichamp is a great solution for problem fermentations. Designed to metabolize fructose in high alcohol conditions (up to...
Continue reading Rescuing Stuck or Sluggish Yeast Ferments
Apr
2012
With harvest coming to an end in most regions of Australia, many of you will be happy to put the challenges of this growing season behind you! Primary and secondary fermentations are now in full swing which brings a new set of challenges, such as producing wines without excessive levels of spoilage compounds.
Three compounds that can impart undesirable characteristics to a wine are acetic acid (vinegar character), acetaldehyde (bruised apple character) and ethyl acetate (nail polish remover character). All three compounds are produced via chemical and microbial processes during and after fermentation, usually below spoilage levels. Certain conditions, however, can...
Continue reading Post Fermentation spoilage compound analysis
Apr
2012
For best results take note of the following:
Sample
-
make sure your Sample spots are as small & concentrated as possible.
-
always allow the spots to dry between applications.
Solvent
-
It is most important to ensure the plate is completely dry between the applications of Solvent & Indicator. Use warm air from a hairdryer to dry the Solvent from the TLC plate. Any acetic acid odours mean more drying is necessary.
-
this is Corrosive & also Flammable. Please wear gloves and safety glasses and handle in a well ventilated area.
-
on drying, if the background of your plate is more yellow rather than blue/green, then your Solvent...
Continue reading Product Tip: Malic acid testing by Thin Layer Chromatography (TLC)
Apr
2012
It is good practice in a winery lab to always degas wine samples prior to analysis of titratable acidity (TA).
This is of particular importance at this time of year for wines that have just finished primary or secondary fermentation, as they can contain a high concentration of dissolved carbon dioxide. In wine, carbon dioxide exists as carbonic acid, which interferes in the measurement of TA to give erroneously high values.
Here are a few options for degassing samples:
-
Add about 100mL of wine to a chner vacuum flask, insert the stopper, attach the side arm to a vacuum pump and gently shake...
Continue reading Lab Tip: De-gas your TA sample to get accurate results
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