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mjbennett
10-14-2003, 12:43 PM
The owner of the brewery I work for is a NA beer drinker and we're looking into producing a NA beer by dialysis. The owner is also a physician and has access to several used dialysis machines. Does anyone have experience using dialysis? *ANY* comments will be appreciated.

--
Mike Bennett
Head Brewer, Southside Speakeasy, Salem OR
Recognized BJCP Beer Judge
mjb<at>efn.org

....Give a man a beer, he'll waste an hour.
Teach a man to brew and he'll waste a lifetime....

lagunitas
10-14-2003, 01:31 PM
Complete a patent search to see if someone (most likely a large brewery) has a patent on dialysis for beer. If someone does, then they will be able to better guide you. A great idea, but feasable? You will most likely need special membranes and if possible, you would most likely want to try electrodialysis as you would have a higher throughput capability. Not much information for you, but a starting place anyway.

Mick
10-20-2003, 02:49 AM
My previous paid job was 9 years as a nurse in a haemodialysis unit. I have a couple of basic powerpoint presentations on dialysis and dialysers (the filters) if you would like me to email them.
Essentially what the process of dialysis would offer is filtration. With a fluid (say for example the wort) on one side of a semi-permiable membane. The dialyser would act as a filter allowing the removal of (usually small) molecules and some water, across to the other side of the membrane. The smaller the pores (or holes in the membrane) the smaller the molecules that are removed. However some dialysers have quite large pore sizes so bigger molecules can be removed.
One of our local milk producers was advertising ultrafiltered skim milk - ultrafiltration being the process by which water is pulled across a membrane in dialysis. Essentially the filtered product contained good ammounts of calcium but the fat remained on the other side of the filter and was sold off as buttermilk.
Filtration has its advantages ( ie removing something unwanted) but having recently tried a beer that was "double filtered" it ended up being a cold gold alcoholic carbonated liquid that was pretty uninteresting to drink.
You could try approaching the dialyser manufacturers such as Gambro, Baxter or Fresenius (all on the net) who would probably be able to send you information about dialysis or put you in touch with someone who kid explain the process more clearly than I can here. Good luck and let me know how you get on.

Cheers and Beers
Mick Garrett
el presidente 2nd
Central Victorian Beer Appreciation Society
Australia

dick murton
10-20-2003, 04:46 AM
Micro filtration systems are available, but currently are only used for gas correction, or for yeast / proten removal. In order to obtain transfer of a soluble product across a semi permeable membrane, you need a relatively low concentration of the selected materila, in this case alcohol, on one side of the membrane, with the source beer on the other. As there are so many other soluble materials in beer, effectively, I suspect that you would need a non alcoholic beer on one side of the membrane to alow only alcohol to cross the membrane - rather defeats the purpose doesn't it. I have a strong feeling that if you merely used carbonated water, or a water carbonated solution of sugar, dextrins etc, with roughly the fermentability profile and pg as the beer, then you would get some transfer of alcohol across, but I would expect other materials key to the overall flavour / mouthfeel / colour of beer to pass across as well.

The only commercial low alcohol production methods I am aware of is by production of low fermentability wort by mashing in at high temperature, which produces somewhat atypical beer, or distillation, normally under vacuum.

I understand that trials with micro filtration to remove yeast & proteins (instead of kieselguhr filtration), whilst effective, also tends to remove some of the flavours & other essential materials, giving a non typical beer - although more recent production trials in Germany have produced commercially acceptable beers.