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

FOOD & BEVERAGE INDUSTRY EDITION

Volume F4 Issue 6 - 27 May 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. "RESULTS NOW" release two more "acid tests"
4. More about "Measuring Food Colour"
5. When to Harvest Wine Grapes?
6. "Biosys" Compact Dynamic Bioreactor - An innovative approach for high BOD industrial effluent
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=ies 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.

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"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".

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"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.

For information about "RESULTS NOW" test kits for TA in a variety of fruits, or ACCUVIN test kits for wine, contact us for details.

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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.

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When to Harvest Wine Grapes? The Effects of Hang Time.

We've been following the (everlasting?) debate about the best time to harvest grapes in order to maximise wine quality and how a grower or winemaker makes that decision. Subjectively, objectively, or both?

If you or any of your colleagues are interested in the text of an article by the noted author and wine columnist  Dan Berger in "Wines and Vines", March 2005 that relates to a dispute between growers and winemakers in the Napa Valley, California, the forum with 600 participants held in the valley by the Napa Valley Grape Growers titled, "Hang Time: A Discussion of its Effects on Vine Health and Vineyard Yields" and Berger's related article in his weekly newsletter, "Getting to the Roots of the Hang Time Issue", please contact us for a free copy.

Lots of interesting stuff from a group of interesting people including Richard Smart and Bob Steinhauer (Beringer Blass)

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"Biosys" Compact Dynamic Bioreactor. An innovative approach for high BOD industrial effluent

The Compact Dynamic Bioreactor (CDB) is a highly-efficient, odourless, automated, combined anaerobic-aerobic waste water treatment plant with minimal sludge production. Although originally designed for small communities, it is ideal for industries whose effluent is high in BOD/COD, such as food and beverage processors.

The key innovative feature of the Compact Dynamic Bioreactor is the "Variopor" carrier material. Variopure consists of small cubes (14 x 14 x 7 mm) of an open, polymer foam. The open structure of the foam provides a large surface area on which micro-organisms live and furthermore guarantees that in the  cubes' interior, the micro-organisms are adequately supplied with nutrients and organic compounds. Compared with conventionally used flocs of micro-organisms, which are active mostly at the surface only, the carrier is much more efficient

Effluent is supplied to the reactor after screening to remove coarse waste. The effluent is mixed in the reactor with the carrier material. Energy is saved since no stirrer is required for mixing; aeration occurs at one side of the bottom of the reactor, resulting in fast, turbulent circulation of water together with the carrier cubes. This circulation also results in the supplied air not going directly from the reactor, but is retained for a longer time in circulation, thus enhancing the exchange of oxygen from the air into the water.

Different varieties of micro-organisms will find a habitat on the carrier material.  Those on the surface of the cube will oxidise ammonia to nitrate, while simultaneously degrading organic compounds. The micro-organisms inside the carrier cube will consume the reduced nitrate to gaseous nitrogen while at the same time further degrading organic compounds. By combining both aerobic and anaerobic steps in the one process, this method of effluent treatment will result in an efficient reduction of BOD/COD and total nitrogen.

The CDB is especially suitable for seasonal food and beverage processing such as wineries. The micro-organisms on the carrier material can be kept alive or restarted depending on seasonal demand.

Containers of a modular standard design with a small footprint are available for a reactor with throughputs as low as. 500L/hour, but in practice, any other size, or kind of vessel can be used. For example, used shipping containers can be modified to suit the basic design. The reactors are usually duplicated and arranged in parallel to assure redundancy and enhance throughput. No special civil works are required; a firm level base, such as  compacted soil is all that is required. Standard polypropylene pipes and fittings can be used for inlets and outlets. The systems are low maintenance and operate unattended except for a weekly routine inspection.

No large clarification basin is required, because the biomass on the cubes is held back just by a grid. The process is therefore stable even during high flow events and the biomass is not washed out. The cleaned, clear effluent leaving the plant is of high quality and can be used for irrigation or recycling.

Changes in flow rate, temperature, or salinity have no negative influence on the high stability of this treatment process. Successful results have even been obtained for industrial wastewater with very high salinity where conventional biological treatment does not work.

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Fun Stuff........

Interesting limos.....

http://www.starlimos.de/limotalk/crazy_e.htm

Strange dictionaries....

http://www.blueray.com/dictionary/index.html

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