Evaluation of protein stability

This method is intended only for visually clear aged wines. The assay involves determining the difference in nephelometric measurements of the original sample and the sample subjected to chemical denaturation of proteins, on the basis of which the degree of turbidity of the wine, expressed in nephelometric turbidity units (NTU), and the final stability of the wine are assessed. Turbidity is measured within the range from 0.00 to 1,200 NTU. 

Nephelometric-chemical laboratory assay.

Parameter: measurement of turbidity [NTU]

Method, device: nephelometric method, photometer/density meter

Method compliant with: B. Zoecklein, Protein Stability Determination in Juice and Wine, Virginia Polytechnic Institute & State University, Virginia Cooperative Extension (1991), 463-015

Sample volume: 100 ml

The research report is issued in the English language.

After completion of the fermentation process and the (first) decanting, the young wine is still turbid. This turbidity, in the form of suspended solids, is affected by dead yeast cells, microscopic fragments of fruit stones or skins and other small solid particles that, over time, naturally begin to sink to the bottom of the fermentation tank, necessitating decanting of the more clarified wine. Before the wine is bottled, it many undergo, if necessary, accelerated clarification, e.g., by adding bentonite, through freezing or sterile filtration, in order to precipitate any unstable substances. Failure to do so can result in turbidity or precipitation in the bottle, and can also lead to microbiological disorders. Stabilisation of the wine before bottling requires checking its protein stability. The qualitative assessment of protein stability also aims to confirm the effectiveness of the fining agents employed or the filtration efficiency.

Turbidity is measured within the range from 0.00 to 1,200 NTU. 

Provision of samples:

The test samples can be delivered in person to the company’s showroom in Łódź (it is possible then to choose the parameters tested and make payment on the spot) or sent by mail / courier service to the address 93-373 Łódź, ul. Pryncypalna 125, with a note saying ‘LABORATORIUM’. Additionally, please include with the package the description of samples and analyses selected (confirmation of order and payment via the Browin online store). Samples sent by mail/courier should be put into a clean, neutral container (e.g. after pure mineral water) and well secured in order to reach the laboratory safely.

Completion time:

The service delivery time is related to the number of ordered analyzes and the current laboratory occupancy and is up to 7 days.

We issue VAT invoices.

Please note: The samples sent are stored for 2 weeks and then disposed of. Any presumptive doubts need to be reported within that period.