Homebrewing a Non Alchoholic Beer - State of the Union

[azscoob]

Ok, so there's no denying I'm a dork. I worked out the math.

V1 = volume before heating
V2 = volume after heating
M1 = mass before heating
M2 = mass after heating
C1 = alcohol concentration by volume before heating, in decimal format. i.e. 5% ABV = 0.05
C2 = alcohol concentration after heating
x = mass of other stuff in beer (i.e. dissolved solids, any other trace liquids, whatever)

Assumptions:
the volume represented by the "other stuff" is negligible and/or constant

Water is 1.0 kg/l or 1.0 g/ml (techincally this is only true at 4 degrees C, but f it, close enough)
Ethanol is .79 g/ml

So, you can calculate the amount of "other stuff" by a mass balance.

x = M1 - mass ethanol - mass of water
mass of each liquid component = volume*density, and volume of each liquid component = total volume*volumetric concentration of the liquid

so
x = M1 - V1*.79*C1 - V1*1*(1-C1)

x doesn't change, and therefore you can also calculate it as a function of the final mass, volume, and concentration:
x = M2 - V2*.79*C2 - V2*1*(1-C2)

you can combine the two and get:
M1 - V1*(1 - 0.21*C1) = M2 - V2*(1 - 0.21*C2)

So if you know your initial ABV, which you do, and you accurately measure the initial and final volume and mass, you can calculate your final ABV.

Wow, I feel waaaay outclassed in the brain department!

I almost understand what you are saying, I need a minute to take it all in.

 

[ajdelange]

1L of a 10% v/v mixture of water and EtOH at 20 °C weighs 981.85 grams.
It contains 100 mL of EtOH which weighs 78.92 grams
It contains 981.85 - 78.92 = 902.92 g H2O.
Thus by weight the alcohol content is 78.92/981.85 = 8.04%

If you calculate x = 981.85 - 1000*.79*.1 - 1000*1*.9 you would find that the "other stuff" in a water/ethanol solution (which contains no other stuff) is 2.85 grams. Something doesn't compute here and that's because volume is not conserved but mass is. Thus you must do everything on the basis of mass.

First, you would have to obtain the true extract (TE) of the beer. To do this measure out a volume of beer at 20 °C into a volumetric flask. Quantitatively transfer to a beaker and evaporate (water bath, low heat...) down to 1/3 the original volume. Quantitatively transfer back to the volumetric flask and make back up to the mark with DI water at 20 °C. Measure SG and convert to °P. Convert SG to density and multiply that by volume to get mass of reconstituted beer. Multiply that by °P/100 to get amount of extract ("other") in reconstituted beer which is the amount of extract in the original sample. As that sample had mass equal to the density of the beer (its specific gravity divided by the density of water) divide the extract of the reconstituted beer by the mass of the beer to get the percent extract per unit mass of beer. Put more simply, the true extract of the beer (TE, °P) is the °P of the reconstituted beer multiplied by the SG of the reconstituted beer and divided by the SG of the beer.

Now convert the specific gravity of the beer to density (multiply by 998.203 grams/L) and then by the volume to get the total mass of the beer. Multiply that by TE/100 to get the mass of extract (which is, by definition, everything that is not alcohol or water) in the beer. Now multiply the ABV by the volume and then by 789.2 grams/liter (the density of EtOH at 20 °C to get the weight of the EtOH. Now you have the weight of the beer, the weight of the extract and the weight of the alcohol. Subtracting the latter 2 from the former give the weight of the water.

Now it's going from here where things get tough. As evaporation takes place the beer loses water and alcohol but it would be difficult to calculate the relative proportions. At the low concentrations of alcohol in beer the water lost is much greater than the alcohol lost. At 10% ABV the vapor contains 13.7 water molecules for every EtOH molecule or 5 times as much water by weight at 98 °C. But as the beer contains 8 times as much by weight the concentration of water in the remaining beer goes up. Looked at another way, the mole fraction of EtOH in a 10% ABV solution is about 3% but in vapor over the mixture at 98 °C it is almost 7%. This is consistent with the theory of distillation. At each "plate" the vapor is richer in alcohol than liquid from which that vapor came.

I guess one could, as I have done above, calculate the mole fraction of alcohol and water (I'd have to make some assumption about the molecular weight of extract - assume it's all maltose I guess) in the beer, get the vapor pressures at a given temperature from that, calculate the mole fraction of ethanol in the vapor, assume dw grams of vapor is swept away and deduct the water and EtOH losses from the mass of beer. Then calculate new mole fractions for the beer, new vapor pressures... and iterate down to the point where a prescribed volume has been lost. Seems like a lot of work and a bit iffy but I guess it could be done that way.

This all suggests a way to remove the alcohol from the beer more effectively: reflux. When doing alcohol determination in the lab the apparatus is such that refluxing occurs and one can monitor this until such time as the condensate's appearance changes. At this point one can assume he got much of the alcohol but distillation is continued in the analysis procedure until the original beer volume is reduced by half. This is then made back up with water (as described above) leaving a pretty unappetizing looking and smelling (I haven't had the nerve to taste it) residue. Bit it is alcohol free.

If you do something less dramatic with the beer, make back up to original volume with DI water and find that the apparent extract of the treated beer is close to the true extract of the untreated beer you can assume that the treated beer has had most of its alcohol removed. You might even try applying Tabarie's principal to estimate the residual alcohol if the apparent extract of the treated (including adding makeup water) beer is lower than the true extract of the original beer.

 

[BrewKnurd]

yah, you're right. i forgot about that damn volume of mixing thing. looks like its a good thing I'm not a chemist.

 

[BrewKnurd]

although you could, since the volume of mixing of ethanol and water is well documented, factor that in to your calculations and I think you could make it all work out with relative accuracy. But its definitely not as simple as I tried to make it.

 

[Erroneous]

I think I know how to figure out how much alcohol is left.

First, drink a shot of 70 proof liquor, wait 30 minutes, take a breathalyzer.
Several hours later drink 12 oz of n/a beer quickly. Wait 30 minutes, breathalyzer. Compare the 2 readings to estimate abv.

Of course there may be a much easier way to say heat up the liquid and push it through a breathalyzer or something.

Edit: if course you would have to repeat several times with different amounts of liquor, and it probably wouldn't hurt to do this several times with different abv beers.

 

[ajdelange]

Of course there may be a much easier way to say heat up the liquid and push it through a breathalyzer or something.

You may have said this in jest but it is something I have considered. Breathalyzers respond to alcohol vapor. They are calibrated with standard alcohol solutions which are placed in a thermostatted (to body temperature) vessel with a stirrer. Air is bubbled through from an aquarium pump and the vapor fed to the breathalyzer. The calibration devices are not that expensive (at least not compared to the gear usually used for measuring alcohol content in a brewery lab). Because breathalyzers are designed to detect levels like 0.01 or 0.02% in blood as reflected through what crosses the blood/lung barrier they are very sensitive and thus lots of dilution is necessary. Might be possible.

 

[passedpawn]

I love where this thread is going. Thanks everyone for the excellent comments.

 

[day_trippr]

I love where this thread is going.[...]

Really? From here it looks like a train wreck with mass casualties...

Cheers!

 

[BrewKnurd]

Really? From here it looks like a train wreck with mass casualties...

Cheers!

I think I got hit by the train.

 

[remilard]

How do I know I've done it? How can I measure my success?

I would make friends with someone at a brewery with a lab as they can do this measurement (and give you a lot of other data too) at minimal marginal expense and labor using equipment costing tens of thousands of dollars. The only other alternative is the labor intensive method AJ Delange described using equipment you probably don't have costing several hundred dollars and techniques you probably aren't practiced at performing.

Worst case scenario, there are places that will run tests for you for like $50 a sample or so. I think one advertises in either Zymurgy or BYO so they are obviously interested in homebrewer business.

Mary Beth Raines attempted several kitchen methods and measured success in a lab, and the success was very poor. She was able to remove most of the alcohol from small samples in the lab, but it never worked with reasonable homebrew amounts in her kitchen.

http://hbd.org/hbd/archive/1609.html#1609-18

The salient point is that many people assumes that what she tried will work and it doesn't, so it is very important to analytically verify success using an accepted method.

 

[azscoob]

I see what you mean about the chemical engineers.

 

[ajdelange]

Mary Beth Raines attempted several kitchen methods and measured success in a lab, and the success was very poor.

I've tried a couple of simplified methods for alcohol assay. I figured if I could give that to home brewers they would really value it but nothing really works as well as the lab methods. I've tried:

1. Reduction of dichromate. Other things besides ethanol reduce it and it takes a photometer to get quantitative data
2. Ebulliometry. Designed for wine but beer has too little alcohol for good BP depression and if you don't dilute the beer at least 1:1 it foams so badly you can't get a reading
3. Breathalyzer with calibration unit. Unstable, inaccurate readings (makes you wonder)
4. Distillation followed by pycnometry (accurate determination of SG with a specifc gravity bottle). This one actually does work quite well but it is quite labor intensive. It requires distillation apparatus (not expensive but not cheap), an good analytical balance (expensive new but lots of used ones avaiable), a pycnometer (special bottle with stopper incorporating thermometer - around $200) http://www.labplanet.com/kimble-kon...ottles-pycnometer-kimble-chase-15123r-50.html. One weighs the empty bottle, fills it with DI water and weighs it again then fills it with distillate and weighs it a third time. From these three weighing the density of the distillate can be deduced and the percentage of alcohol looked up in the AOAC or OIML tables. Typically the beer will also be weighed as will the residue from the distillation which gives the specific gravity of the beer (apparrent extract) and its true extract as well. The downside is that each weighing takes some time. Plan a whole afternoon to analyze a single beer.

For the record I am an electrical engineer.

 

[orangehero]

N/A beer can also be made through special mashing and fermentation techniques.

 

[passedpawn]

N/A beer can also be made through special mashing and fermentation techniques.

There is a Sacc species (ludwigii) that doesn't produce ethanol. I wonder what that tastes like?

 

[passedpawn]

I have a RO system that I'm thinking about using to strip the alcohol. From what I've read, it works great but you need to dilute the beer down a bit to make up for water that will pass through the membrane.

This gets around the problem of losing all the flavorful esters in the various distillation methods.

I just need to figure out what type of membrane to use.

 

[remilard]

There is a Sacc species (ludwigii) that doesn't produce ethanol. I wonder what that tastes like?

It doesn't produce characteristic beer esters etc. According to Fix, it tastes like hopped iced tea.

 

[Ryush806]

Might not want to mix your beer with castor oil but an interesting article nonethless:

http://www.techbriefs.com/component/content/1830?task=view

 

[H-ost]

This is awesome...

I'm subscribing so I can continue to pretend to understand most of this.

 

[passedpawn]

I have a RO system that I'm thinking about using to strip the alcohol. From what I've read, it works great but you need to dilute the beer down a bit to make up for water that will pass through the membrane.

This gets around the problem of losing all the flavorful esters in the various distillation methods.

I just need to figure out what type of membrane to use.

I found this while looking for a RO solution. Lots of good information here. RO systems are available at the hardware stores, so it would be a good homebrew solution if the membranes are easy to get also. Might take two passes to sufficiently reduce the ethanol? Also, wonder if the march pump creates enough pressure to make this work.

Physical Removal of Ethanol

It seems that RO is a viable solution. I have to find the right membrane. I think one of these might be right, but not sure:

http://www.aquatechnology.net/reverse_osmosis.html

 

[ajdelange]

Dialysis (very closely related to reverse osmosis) is used in the commercial production of low alcohol beer. I would think that getting the right membrane would be critical. See www.scientificsocieties.org/jib/papers/1994/1994_100_4_287.pdf. I wouldn't think that a membrane intended for RO of water would be suitable and the housing would have to be different. Whereas permeate simply flows through the membrane and out to the atmospheric or pressure tank in an RO system dialysate flows counter to the beer on the other side of the membrane in dialysis.

 

[vicratlhead51]

This is awesome...

I'm subscribing so I can continue to pretend to understand most of this.

I second this statement

I've been wanting to try this so I can have some to give my dad who likes beer but can't drink and just so ill have some to enjoy when I don't want the effects of alcohol. I was curious though any suggestions for a base beer? Would a malt driven recipe be better or would a hop driven one work better as long as you do the hop tea thing. Has anyone thought of adding hops in while "boiling" off the alcohol? I was kind of thinking it'd add something different, a little like a cross between dryhopping and whirlpool hopping. Anyway, subscribing since I find this totally interesting and would love a NA beer that isn't a crappy light lager.

 

[hbtasdfg]

Another method probably more flavorful than boiling that nobody has really discussed here is making a "small beer". Small beer was a traditional product used before the mid 20th century that was 2-3% alcohol. It was made because it was much safer than the iffy water supplies at the time and for nutritional value in the era before vitamins were discovered. You could make one with a starting gravity so low you end up under 2% ABV or 0.5% even which is technically considered non-alcoholic. You could manipulate the percentage of fermentables you use by using extracts to control body too. Starting gravity would probably be below 1.020 and you get whatever hop flavor you like in the finished product without destroying it by boiling after.

 

[vicratlhead51]

Another method probably more flavorful than boiling that nobody has really discussed here is making a "small beer". Small beer was a traditional product used before the mid 20th century that was 2-3% alcohol. It was made because it was much safer than the iffy water supplies at the time and for nutritional value in the era before vitamins were discovered. You could make one with a starting gravity so low you end up under 2% ABV or 0.5% even which is technically considered non-alcoholic. You could manipulate the percentage of fermentables you use by using extracts to control body too. Starting gravity would probably be below 1.020 and you get whatever hop flavor you like in the finished product without destroying it by boiling after.

I'm actually planning something like this for my next beer. I was going to try a partigyle trippel and cap it off with some roasted malt and crystal malt to make a small red from the second runnings. The second beer should have an OG under 1.040 if I figured it out right. Making extra unfermentables by monkeying with the mash would be an option too except I'd imagine unless you ramp up the hops you would wind up with a really sweet thick beer which for me wouldn't work for the times I'd want a NA beer like working around the house or doing some kind of work where I wouldn't want my coordination impaired. I'm a big enough clutz without being drunk . On the other hand it might make a really nice IPA if you don't mind the extra calories the unfermented. Sugars add to the beer. You could hop the living hell out of it and not worry about it being too bitter.

On a side note, how would this affect the shelf life of the beer? Without alcohol in it does it go bad faster?

 

[hbtasdfg]

with a small beer the whole point is to have just barely enough alcohol to act as a preservative (2-3%). If you go lower you probably will get something that is not really shelf stable and might have to look into pasteurizing stovetop after carbonation is complete. If you keg you might have to sulfite/ sorbate like a wine to preserve. There is a thread about stovetop pasteurization somewhere in here just search it.