The Latest News & Information from Colour Technologies Australasia and The Novasys Group

GENERAL EDITION

Volume G4 Issue 2 - 3 June 2005

Table of Contents

1. Wine Filtration for the small winery and home winemaker
2. Nominal" vs. "Absolute" Filtration Standards. What do they really mean?
3. Stormwater Pollution Prevention...Are Gross Pollutant Traps THE Answer?
4. "RESULTS NOW" release two more "acid tests"
5. More about "Measuring Food Colour"
6. OilTrap Environmental Introduces a New Generation of Washwater Treatment
7. Fun Stuff........

Wine Filtration for the small winery and home winemaker

Most red wines self-clarify in a few months, and they usually do not require special clarification treatments. White and rose wines are different. Here, any lack of clarity will be very evident, and most white or rose wines require one or more specific clarification steps. Sometimes getting a white or rose wine clear and "bottle bright" without using some kind of filtration is difficult. Consequently, practically all commercially produced white and rose wines are filtered before they are bottled. Home winemakers prefer to produce brilliantly clear wines, although it is not essential unless they wish to enter competitions.

Practically all of the yeast cells can be removed from wine by simple, inexpensive filtration. Medium-dry and sweet wines can be bottled with little worry the residual sugar will start fermenting, and wine quality does not suffer significantly when the filtration is done properly. extreme levels of filtration are not necessary or desirable for normal wines. Many winemakers believe the less treatment a healthy wine receives, the better the quality of the finished product. These winemakers pursue a minimum filtration philosophy for the production of fine wines, but minimum filtration does not mean zero filtration. Producing brilliantly clear white or rose table wines without using some reasonable level of filtration is difficult and sometimes impossible.

Both "pad" type filter assemblies and "cartridge" type filters are used by small wineries. Pad type filter assemblies are expensive. However, when large quantities of wine are filtered, the depth type filter pads are quite economical. For the smaller commercial winery=wineries and home winemakers, cartridge filters are an inexpensive option.

Cartridge type filters consist of filter materials made in the shape of a hollow cylinder. The cylindrical filter cartridge is housed in a plastic or stainless steel container. Wine flows into the housing and through the filter cartridge from the outside to the inside. After passing through the filter material, the wine flows out of the housing. Cartridge type filter housings made of plastic are used extensively for domestic water filtration. These plastic housings are made in large quantities, and they are inexpensive. Filter systems can be built from inexpensive plastic housings simply, so small and home winemakers often use cartridge type filter assemblies.

Filters can be purchased with porosities ranging from 50 microns to about 0.2 microns. Two different scales are used to rate the porosity of cartridge filters, and a large difference in particle retention ability exists between the two scales. (See article below)

A filter assembly suitable for the home winemaker can be easily made from standard, plastic 10-inch housings  such as  those used to improve drinking water quality.. This type of filter assembly can be used with any small transfer pump that can deliver a pressure of at least 10 psi.

One-micron (nominal)  cartridges cost are suitable for rough filtration of all types of wine. Either 0.5-micron (nominal) cartridges,  or 0.2-micron (nominal) cartridges can be used for polish filtration. A 0.2-micron nominal cartridge is preferred for final filtration of white and rose wines. This type of cartridge filter assembly can produce excellent wine clarity, and it gives the small producer a very practical filtration system. Best of all, the filter can be easily assembled from standard parts for a few dollars.

"Silvex" bacteriostatic 0.5 micron absolute, (0.2 micron nominal) candles and cartridge filter elements manufactured by JP Ceramics and supplied by Novasys are inexpensive and will fit all standard 10" housings. Novasys can supply cartridges to fit existing housings or both food grade housings and cartridges. These elements will remove all particulate matter remaining after rough filtration, including any residual bacteria harmful to either the wine quality or to human health.

For details of the JP Ceramics filter elements for both wine and water, please ask for a brochure.

Back to Top

"Nominal" vs. "Absolute" Filtration Standards. What do they really mean?

Two different scales are used to rate the porosity of polymer and ceramic filter elements and a large difference in particle retention ability exists between the two scales. "Nominal" filters are rated using a 50 percent criterion. For example, a 1-micron nominal filter will pass about half the 1-micron particles present. "Absolute" filters use a more stringent standard. Absolute filters use a 10 out of a million criterion. A 1-micron absolute filter only passes ten 1-micron particles out of a million. The other 999,990 1-micron particles are retained by the filter.

The 0.5 micron ceramic filters manufactured by JP Ceramics and provided by Novasys are rated at 0.5 micron absolute. That rating means that to meet the standard, only one 0.5 micron particle in 100,000 will pass the filter; in fact the JP Ceramics filters exceed that standard.

Some suppliers of filter elements describe their products using the "nominal" criteria. If  0.5 micron "nominal" is quoted, that means 50% of particles of 0.5 micron will pass the filter. NOT a very effective barrier to bacteria!

Quoting "nominal" data can be misleading if the rating is not explained. So let the buyer beware; check the criterion used before purchasing so that you can be sure the filter element is, "fit for purpose".

Back to Top

Stormwater Pollution Prevention...Are Gross Pollutant Traps THE Answer?

The answer must be no. Gross Pollutant Traps are part of the answer only!

There has been a raft of publicity lately about the state of our rivers and waterways that does not make for happy reading or listening. One reaction to this has been to recommend the  installation of Gross Pollutant Traps to stop pollutants entering the stormwater drainage system.

By their very nature, Gross Pollutant Traps are designed to capture relatively large objects; bottles, cans, plastic bags and other relatively large objects. BUT... what about small objects, cigarette butt size and smaller? What about grease, oils and fuels such as  diesel and petrol? Sediments, dust, particles from brakes and motor vehicle engines that may contain heavy metals or asbestos? Animal urine and liquefied faecal matter?

There is no guarantee that GPT's will capture any of these smaller size pollutants unless they find their way permanently into the inside of the bottles, cans etc. that are thus trapped.

Then there is the question of cost; initial cost and maintenance. Most GPT's are not cheap and need to be cleaned out before they overflow. Retrofitting into older suburban streets or industrial sites may be impossible and/or prohibitively expensive.

The UltraTech range of disposable or reusable catch basin devices; DrainGuards, KerbGuards and GrateGuards that capture large and small debris down to sediment size, as well as hydrocarbons, are both cheap and effective. Users can choose the most appropriate device depending on the nature of the pollutant in their area. The disposable devices can allow water to flow into, but prevent any pollutant entering a particular drain, or capture up to 75% of ALL solid and undissolved pollutants in the stormwater stream, including hydrocarbons. The reusable devices are designed to capture large quantities of solid debris and sediments; up to 250kg per device. If spills occur, the UltraTech DrainSeals prevent any material escaping into the stormwater system.

Neither UltraTech nor ourselves pretend that the UltraTech devices provide the only answer to the problem of stormwater prevention pollution, but we do contend that they can play a significant part in a Total Stormwater Pollution Prevention Plan including Best Management Practice that includes Water Sensitive Urban Design, Gross Pollutant Traps, spill prevention and/or cleanup, preventing and detecting illegal connections to stormwater drains, education and enforcement.

At the very least, every company, municipality and contractor should maintain a program that includes good housekeeping, a preventive maintenance, visual inspections, a spill prevention and response policy, sediment and erosion control, and runoff management.

For information about UltraTech stormwater management products, or guidance on stormwater management at your site, please contact us.

Back to Top

"RESULTS NOW" release two more "acid tests"

"RESULTS NOW" have added Mangoes and Strawberries to the range of fruit for which Titratable Acid test kits are now provided.

As with the other test kits for TA in fruit, the kits are available in packs of 10 and 20 and at the same prices; $31.00 for 10 tests and $59.00 for 20 tests (excl. GST).

No laboratory or experience is required. The kits contain everything needed.

Back to Top

More about "Measuring Food Colour"

Our views about the sensory attributes of food related to appearance seems to be supported by a recent article by Dean Duxbury in the US Food Technology magazine, (January 2005, Vol 59, No. 1) and reprinted in Laboratory magazine.

Duxbury quotes Oregon State University's Food Resources Web site (http://food.oregonstate.edu); "The most frequent use of food colour measurement is related to developing objective indices of food quality". He goes on to state that sensory attributes of food related to appearance are the most susceptible to objective measurement.

As is well known in the field of colour science, appearance is the combination of chromatic,, or colour, attributes and geometric, or spatial, attributes. Duxbury says that worldwide literature reviews indicate that there been a lot of use of the theory of colour in both of the above areas related to food, yet, "there is still a lot not known or understood". That isn't news to us! The sensory attributes of food related to appearance often seem to take third place behind taste and smell when sensory attributes are discussed, yet taste and smell are still assessed subjectively by human panels. Assessment by panels is expensive and time consuming, but until objective methods become available, unavoidable. Nevertheless panels are sometimes used for colour assessment, particularly in the wine industry and it is hardly surprising as reported anecdotally, "results were all over the place".

Colour is an important attribute to the food industry. Consumers frequently look at a food product and make a decision based on overall appearance, including colour. Food processors use food colours to optimise the attractiveness, appeal and presumptive appetizing features of food to the consumer.

The adoption of objective methods of assessing colour and appearance using instrumentation such as that supplied by HunterLab has been taken on enthusiastically by some sectors in the food industry, and hardly at all by others. Where objective instrumental measurement is scarcely used, maybe it is because in that sector, ""there is still a lot not known or understood".

If you would like to know or understand more, or would simply like a reprint of Duxbury's article, please contact us.

Back to Top

OilTrap Environmental Introduces A New Generation of Washwater Treatment

Planes, trains and automobiles, Trucks, buses, trams, ships, bulldozers, tractors, cranes, conveyors, earth moving and mining equipment and shipping containers. All get dirty, all need washing and the dirty water needs, (or ought to be), cleaned up for re-use, or before discharge to the environment.