Measuring ABV directly?

[Oberon67]

Hi, all.

Is there any instrument less expensive and more readily available than a High-Pressure Liquid Chromatograph (HPLC) to directly test the alcohol content of our beer?

-Oberon67

 

[JordanKnudson]

I don't have an answer, I am just replying so I can keep up with other replies.

I remember that not too long ago I saw "send-away" testing kits for sale that let you send your homebrew to a lab where they would test your avb, ibus, etc...I'm sure others remember what this was better than I do. But anyway, it was kind of pricey for measuring the numbers on one single batch, so I never did it. Wonder if there's a cheaper way (besides the usual FG-OG numbers game, which is fine with me most of the time).

 

[sandyeggoxj]

White labs will test it for you. I'm sure bsi and omega would do that as well.

 

[JordanKnudson]

White labs will test it for you. I'm sure bsi and omega would do that as well.

Right! It was the White Labs send-away tests I was remembering.

 

[Anatidaephobic]

I used to work in a brewery QC lab. We did it by the ASBC distillation method. Basically you take 250mL of degassed beer, dilute it with some water, and then distill off ~225mL. Alcohol boils at a lower temp then water, so all the alcohol should have boiled off into the collection flask before you even come close to 225mL. The distillate is then diluted to 250mL. Alcohol is less dense than water and should be the only other major constituent of the distillate, so by taking a hydrometer and temperature reading of the diluted distillate and comparing it to an alcoholometric table, you can calculate the alcohol content in a similar manner to how you would find the gravity of beer or wort.

The ASBC requires a membership to view their methods, but you can find a similar method here: http://www.slideshare.net/sreeremyasasi/ethanol-determination-by-distillation-2

 

[jzelina]

Oh is that all there is to it :cross:

 

[Anatidaephobic]

As easy as pie Not exactly cheap equipment though. A good hydrometer and lab glassware would cost upward of $500. But there's no consumables in the process, and it's still orders of magnitude cheaper than a HPLC machine.