The Application of PVP in Brewing£º
Low alcohol wine made from plant-based materials such as barley, corn, hops, and grapes is rich in various proteins and polyphenols. These proteins and polyphenols exist in the wine as colloidal particles. When left for a long time or at temperatures below 0 degrees Celsius and above 20 degrees Celsius, they may form flocculent precipitates, causing the wine to become cloudy and affecting its flavor. Some polyphenols are carcinogens and harmful to the human body in the wine. Turbidity is particularly common in beer, caused not only by the coagulation of colloidal particles mentioned above, but also by the acidification caused by certain biological impurities. Beer can also produce cold turbidity when refrigerated. These are all technical issues that must be addressed in the beer production process, otherwise the quality of the beer cannot be guaranteed. Polyphenols that can easily cause beer to become cloudy and affect its quality are mainly anthocyanins, catechins, and flavonoid polyhydroxy derivatives. In the air, these polyphenolic substances are either oxidized to quinones or polymerized into polymers that are more prone to settling. Then, they are precipitated by hydrogen bonding between hydroxyl groups and O atoms in the molecules and protein molecules. These precipitates are the reasons that affect the stability, color, and flavor of beer. To solve this problem, it is necessary to remove the precursors that cause coagulation and precipitation phenomena - polyphenols.
In production, methods to solve the phenomenon of beer flocculation and sedimentation include adsorption filtration, precipitation separation, protease decomposition, etc. Cross linked PVP (PVPP) is used in beer precisely because it has a similar protein structure, so it is adsorbed and separated by chelating with polyphenols. PVP or cross-linked PVP used in brewing is generally insoluble, so it can be easily removed by filtration without remaining in the beer.
The steps for PVPP treatment of beer, yellow wine, etc. are as follows:
After the beer is treated with diatomaceous earth and filtered, PVPP is added by metering, stirred for 150-180 minutes, allowed to stand for 5 minutes, filtered, and the filtrate is packaged. The filter residue is regenerated with 1% NaOH solution at 85 degrees Celsius, and then rinsed with 85 degrees Celsius hot water to a pH of 7 to obtain the regenerated PVPP, which can continue to be used.
The cross-linked PVP produced by our company for brewing is called PolyFilter, with specifications of PolyFilter VT, PolyFilter 10, and PolyFilter V. We have conducted industrial experiments with multiple domestic breweries and achieved basically consistent results. After treatment with PolyFilter, the shelf life of beer can be extended by more than 180 days, and for specialty beer, the shelf life can be extended by 300-360 days.
The comparison between PVPP and other stabilizers is shown in the table£º
Stabilizer | Method of action | Beer stability | Beer color | Beer foam | Residue in beer | Approved for use |
PVPP | Adsorbator-R and its ability to cause turbidity and fog Combined with polyphenols | There are clear improvements, Storage period: 9-12 months | Almost unaffected | Not affected | By filtering method Can be completely removed | Around the world |
Silica gel | Adsorbents and Molecular Proteins Combined with | Improved, storage period Limited to 6 months or less | Almost unaffected | Foam stability Slightly reduced | By filtering Completely removed | Around the world |
Protease | Decompose proteins through hydrolysis pathway | There has been improvement | Almost unaffected | Foam is unstable | Must be sterilized | Partial regions Restricted use |
Tannin | Form complexes with proteases | There has been improvement | Almost unaffected | Reduce foam stability | Not entirely from beer Remove from alcohol | Partial regions Restricted use |
Application of PVPP in non-alcoholic beverages£º
PVPP has been widely used not only as a stabilizer in beer, but also as a good clarifying agent and stabilizer for tea beverages, juices, vinegar, soy sauce, other liquid foods, and health foods. In many cases, due to the presence of small amounts of phenols and polyacids in some liquid foods, they can precipitate and become cloudy if left for too long. In the production and processing process, adding a small amount of PVPP can improve their clarity, prevent turbidity, stabilize color, improve taste, and extend storage time.