BREWING
minimise thermal load on the beers. MIS is a contract processor and packager and uses the system to produce beers and wines for contract customers down to 0% ABV. Luc feels that thermal systems and the SIGMATEC in particular represent the lowest operating cost technology available to produce such beers. Vacuum distillation Mechanical versions of vacuum distilla- tion are available which use the move- ment of the machine and hence the beer to increase the surface area for evapora- tion and thus reduce the contact time of the beer and the heating surface. In the Centriferm from Flavourtech the beer is sprayed via a nozzle onto the top side of a cone spinning in a cen- trifuge and the beer is rapidly distributed across the surface of the cone to form a thin lm (circa 0.1mm). Steam is passed through the machine into the underside of the cone causing evaporation of the ethanol and other volatiles. Because the liquid lm is so thin temperatures as low as 35 ° C can be used and it claimed the machine has minimal thermal impact on the beer. The vapour from the Centriferm requires condensation and recti cation before the aroma volatiles can be returned to the dealcoholised beer. The system is principally marketed as an evaporative drier for food and there are concerns over DO 2 pick up through its operation. Another mechanical vacuum distilla- tion option from Flavourtech is the spin- ning cone column (SCC). The SCC has upward fanning cones xed to a rotating column. Another series of cones are xed to the chamber wall surrounding
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Year UK AFB sales 2014-2018 (source: GlobalData)
rectifying column. Rising through the stripping column as a counter current ow are vapours produced by heating dealcoholised beer which selectively remove ethanol from the beer. Although there is some selectivity, other important volatile components are removed from the beer into the distillate so the system undertakes further recti - cation in an aroma recovery unit. These volatiles are then added back to the beer under pressure after cooling with glycol. Although this element of the system adds back some of the aroma removed through evaporation, some 70-90% of the higher alcohols and esters are lost during processing according analysis undertaken in 2005. Luc De Baerdemaeker, Operations Director at MIS SA in Courcelles, Belgium, operates the SIGMATEC system. Luc uses a process temperature of 30 ° C to
Modern versions are a great deal more palatable and, in this article, I will discuss today’s technologies for producing AFBs and technical options for achieving a product with the best possible value, avour and stability. The methods for producing AFBs can be split neatly into two approaches. Removing the alcohol from an alcoholic beer (physical) and producing a beer with little or no alcohol in (biological). Physical methods can be further split into membrane technology and thermal technology. Thermal dealcoholisation When AFBs rst started to look like a nice little earner the volatility of ethanol in comparison with water and solutes led brewers/chemical engineers to employ heat to evaporate the ethanol. It is important to note that evaporation is not boiling so we are not talking about sim- mering the beer gently over a low ame. Thermal systems are the only deal- coholisation technology which can ef - ciently remove all the ethanol from beer. Another signi cant bene t of thermal systems is the production of food-grade ethanol which can be sold on for use in other drinks. Applying heat to beer, unless you are making mulled ale, is substantially deleterious to avour, so modern thermal systems are designed to be as non-thermal as possible. Use of a vacuum increases the rate of evap- oration of ethanol thus enabling removal at a lower temperature. Vacuum recti cation In the SIGMATEC system manufac- tured by API Schmidt, beer is heated to 42-46 o C in a heat-exchanger and fed to the top of the stripping section of a
Parameter
Unit
Pre VR Beer
Post VR AFB
OG
% Weight
11.59
2.46
Ethanol
% v/v
4.99
0.48
Bitterness
EBU
24.9
25.5
1-propanol
mg/l
6.7
0.8
2-methyl propanol
mg/l
11.2
0
2-methyl 1-butanol
mg/l
15.2
0
3-methyl 1-butanol
mg/l
52.8
0
Total higher alcohols
mg/l
104.7
38.3
Ethyl acetate
mg/l
16.9
0
Iso amyl acetate
mg/l
1.9
0
2-phenyl ethyl acetate mg/l
0.4
0.03
Total esters
mg/l
19.6
0.04
Table 1: Beer attributes before and after vacuum recti cation (adapted from Branyik et al. 2012)
BREWER AND DISTILLER INTERNATIONAL ● 2
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