Brewing success

Louise Smyth

Vincent Fleck details a case study that showcases the merits of an innovative pneumatic agitator that’s proving popular in the craft beer industry 

There are increasing numbers of craft beer breweries across the world. As the products in this flourishing sector become more popular, plenty of operations are moving away from the ‘home shed’ type of model to near-industrial facilities.

Part of the process of producing special beers – such as the very popular India Pale Ale (IPA) – takes place in a brew kettle size of 5,000-10,000 litres.

Suspending a big quantity of dry malt grist into water (1:3), at a viscosity of approximately 200 mPas, it is necessary to keep the different particles sizes and densities well suspended.

A fast heat transfer is required in order to measure the right temperature for process control. A fast ‘bottom up’ homogenisation in a bigger and higher vessel is also needed, alongside as little shear force as possible for the following filtering process.

The Flecks Mixer has gathered a great deal of positive experience in this application since it was launched two years ago. The mixer is already being deployed in five of the larger craft breweries.

The advantages of this system include: simple application; low cost investment; low energy demand; robust design and reliable operation. The combination of the Flecks Mixer with conventional low powered agitators is also a key selling point.

Another important application in the brewery sector is that of fermentation tanks up to 7m height that have the problem of temperature segregation. Because of the exothermic reaction during yeast fermentation, a frequent scenario is higher temperatures than desired on top, and too low temperatures at the bottom.

For this application, shear forces should be extremely low, and all homogenisation must be done under pressure of up to 2 bar. The Flecks Mixer easily performs all of this via just four movements per hour.

Greater control

For the company behind the Flecks Mixer, the biggest emphasis over the past year year was the development of a PLC control system by networking the Siemens Simatic S7-300 system.

Although the mixing system may seem very simple, it can actually be operated in an extremely smart and flexible way to adapt to various products.

This is done via the following freely programmable parameters: speed of up/down movements (depending on viscosity, which may change during the process); frequency of disc movements (to adapt to various particle sizes of suspended matters); height of movement (to either keep the disc under the liquid surface – to avoid oxygenation, or to lift it a little above the surface for suspending dry matters into the liquid, or lift it completely to the top/or keep it at the bottom for a rest).

As a result the system can be easily implemented in almost all industries into existing or new tanks – and it can communicate with existing process automation systems.

What’s next?

Despite this recent innovation, there is still a lot to be done with the Flecks Mixer. Its inventor is now focused on discovering which specific problems in various industrial processes could be solved with the system. Only the experts in the different industries can truly evaluate the opportunities to improve their production with it. But the above report about craft beer production may provide some hints as to how others can benefit – as well as create a thirst for a nice IPA. n

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Vincent Fleck is a biotechnologist and head of Flecks Brauhaus Technik Austria.

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