Blending - mission possible

Complete pre-assembled plant for making blended alcoholic beverages

Blended alcoholic beverages, mainly spirit or beer based, are still gaining in popularity. For production facilities, making these beverages means that a multiplicity of components have to be mixed together before the product is ready for bottling. In order to cut costs, new installations often take the form of pre-assembled and pre-tested components called “units”. A further advantage is that it is possible to determine the cost of installation precisely beforehand.

Blended alcoholic drinks are manufactured on the basis of a “spirituous liquor” or spirit. These are alcoholic drinks containing distilled alcohol, generally with more than 20% pure alcohol by volume. Spirits are manufactured either by distilling fermented juice, mash or marc, or by mixing neutral alcohol with water and other ingredients.

Spirits divide up into two main categories:

True spirits distilled from wine or made from brandy
Liqueurs - a mixture of alcohol, water, sugar and other ingredients.

Spirits are subject to a state “spirit monopoly”: the exclusive right claimed by the state, either as a source of income or for reasons of agricultural policy, to manufacture and/or sell spirits. The pure ethanol traded by the state monopoly board, the Bundesmonopolverwaltung für Branntwein (BfB), is subject to spirit duty. Spirit in this sense is synonymous with neutral alcohol, ethyl alcohol or ethanol.

For the metering of the alcohol/water blend produced, mechanical alcohol meters are among the techniques licensed by the BfB. Due to the mechanical structure on which these meters operate, only low throughput is achievable. EU funding for the manufacture of bio-ethanol and the use of new process technologies has led to considerably higher flow rates per hour needing to be measured today.

GEA Diessel has been granted approval by the BfB for an alcohol mass measuring device to meter alcohol/water mixtures. The units, which are each individually approved, can cover any metering ranges desired.

The approved metering equipment, mounted as a complete unit on a skid, consist essentially of

a mass flow meter
a measurement converter
a density measuring system
a process computer
a printer
a deaeration system.

These complete units are supplied ready for connection, and have been pre-tested at the factory. It is therefore easy to calculate the time and expense required for installation and commissioning. If required, the units can be supplied with double containment: no additional housing is necessary.

Reception and blending of duty-paid alcohol

For many facilities where alcohol is processed, the reception and storage of the ethyl alcohol is a technical problem. On the one hand the facility is interested, for economic reasons, in receiving alcohol in large quantities at once. But storage of ethanol with an alcohol content of around 96.5% by volume requires special inspection by the trading standards authorities and the fire brigade, associated with the necessary protective measures against explosion.

Things are made much simpler if the alcohol is blended with drinking water at the time of reception. Storage of an alcohol/water mixture with an alcohol concentration preset at the desired low level is substantially easier. Through the use of appropriate analysis equipment, the alcohol content of the mixed product can be measured to an accuracy of better than 0.1% alcohol by volume. The mixing equipment required to solve this problem is very economical on space: four square metres is enough to relieve the operator of many worries. An important aspect of the system is its integration into a superordinated computer system, in order to achieve complete internal accounting for the alcohol used.

Metering equipment to receive alcohol and directly mix it with water simplifies storage, since no special fire or explosion protection measures are required.

Batch mixing equipment

Due to the great number of different recipes and the constant need to adapt to market requirements, a very great variety of liqueurs of consistent quality have to be produced within a very short time. The use of a single metering system for all ingredients guarantees high blending precision. Errors during the starting of a recipe-controlled batch are practically excluded. A testing and deaeration lantern monitors the precision of the metering technology automatically and with computer assistance.

The design of the batch mixing equipment allows for a variable number of up to twelve ingredients to be connected without any additional apparatus being required; the basic model is equipped with connection points for five ingredients, but the design incorporates the necessary piping for this number to be increased.

Ingredients such as alcohol, water, sugar solution and additional ingredients 1 and 2 are generally required in all recipes. The connections for additional ingredients 1 and 2 can be allocated as required. The recipe may require the connection of an external dissolving vessel with controlled water dosage and agitator control.

As the batch mixing equipment is operated on the so-called full hose principle (before the start and after the end of the dosing, the plant is filled with potable water), product changes can be effected immediately without any cleaning in between. The recipe control determines the sequence in which the ingredients are added. Generally speaking, liquid sugar is added as the last but one component, since other ingredients will stick to the sugar and be flushed through with

it. Finally, potable water is added in the quantity determined by the recipe. Thus the batch mixing equipment is filled with water, as far as the mixing tank. The product can be changed immediately. However, if ingredients with a particularly pervasive flavour such as aniseed are used, CIP cleaning is required.

DIMA-S batch mixing equipment and tandem vessels

Feasibility study to assist with project planning

The decisive area for a new production run is the mixing and starting area. The question is to whether continuous or batch mixing equipment should be installed must be investigated beforehand by means of a feasibility study. Such a study is designed first and foremost to reveal any possible contradictions between the aim of the project and the existing state of knowledge. In many cases, such a feasibility study will already come up with solutions or new possibilities for products or projects.

Among the decisive criteria for the installation of continuous blending equipment might be the following:

the plant requires little space, so can be installed in a very restricted area;
no assemblies of mixing tanks are required;
energy can be saved in the planning of the CIP equipment;
concentrates of consistent quality are constantly available in appropriate container sizes
high production volumes of up to 50,000 l/h;
the same product is to be manufactured over a considerable period of time;
manpower requirements are low;
the process is highly accurate, thanks to the use of precise flow metering equipment;
excellent regulation by digital control, accurate to the pulse;
monitoring with analysis systems (Brix, CO2, conductivity, colour);
automatic correction;
accounting for the various ingredients;
remote control of all plant function;
a compact, factory-tested unit, ready for connection;
skid-mounted
low installation and commissioning costs.

The functioning of continuous blending equipment

The ingredients are propelled by centrifugal or rotary piston pumps. All mass or volume flows are continuously recorded by the flow metering equipment and the values transmitted to the control unit for regulation. The control unit compares the metered values with the predetermined proportions of the individual ingredients, and controls the regulating apparatus in such a way as to comply precisely with the predetermined values. Particular emphasis is laid upon a high degree of reliability in the manufacture of the products. A variety of testing procedures are used to monitor production.

Conductivity, colour or density measurements can be used to monitor the concentrates or basic materials, to ensure that there is no possibility of a wrong ingredient being used and/or that the ingredients used comply with the specification.

This measure is important especially if a variety of products are manufactured or different containers attached. If necessary, downstream carbonation will serve to impregnate the beverage.

Mixing a beer-based beverage

New attitudes and an increased demand from consumers for a refreshing, slightly alcoholic drink call for a great variety of different beer-based drinks in addition to the classic shandy and “Berliner Weisse”. Just as ethyl alcohol forms the basis for the manufacture of a liqueur, so beer brewed in accordance with the German purity law is fundamental to a beer-based drink and its most important ingredient.

The ideal choice of mixing technology may lie somewhere between batch-mixing and continuous blending.

Blending by the tandem procedure

The advantages of the rapid production of the starter concentrates by the batch procedure and the high blending performance of continuous blending equipment can be combined by using the tandem procedure. Two vessels, arranged one above the other, function as a mixing and a storage vessel respectively. A mixing unit with a throughput of around 2,500 l per hour supplies the various concentrates to the upper vessel. Potable water is used in small quantities to flush out the pipe between the mixer and the tandem vessel.

Good mixing of the concentrates in the upper tandem vessel is ensured by the use of an agitator. When the stirring time has been completed, the connection to the lower vessel is opened. The concentrate runs into the lower vessel by gravity, and from there is fed into a downstream continuous blending unit in which beer is mixed with potable water, sugar and concentrates. A new batch using the same concentrates is then immediately started in the upper vessel.

It generally takes substantially longer for the beverage to leave the lower of the tandem vessels than it does for the new concentrate to be started in the upper one. It is thus possible to work continuously with the entire unit. Carbonation equipment is incorporated into the plant for subsequent impregnation.

Summary

Thanks to improved metering technology and the enhanced reliability of analysis techniques, continuous blending is highly suitable for facilities with a high throughput. The use of all the systems described is justified if a suitable building is available and if there is a frequent change of product with the use of dry materials in the starting stage. The feasibility analysis will answer this question.

The author:
Wolfgang Zenker, born 1952, studied at Hildesheim College of Electrical Engineering to become a state-examined electrical engineer. Since 1987 key account manager, soft drinks and spirits industries, in the Food & Beverage Systems division of Diessel.