Strength of Finished Brew

[pe1850]

For my standard brews I gauge potential alcohol from specific gravity. For my experimental stuff I want, as in all good alchemy, controlled conditions and accurate measurements. What I am missing is something to tell me the alcohol content of my final product. A brew shop owner did try to sell me a special hydrometer claiming it would do the job but refused to demonstrate it. Surely there is something, like litmus paper, that will tell me or allow my granddaughters to avoid spiked drinks. The police have devices for this but there seems to be a veil of secrecy. I would appreciate some help and / or ideas on possible avenues to explore.
Peter

 

[Aleman]

To determine the alcohol content of a drink you need something like an ebulliometer . . .but they are expensive and generally not something you can carry around.

Police and customs use bench top ebulliometers to ensure that the measures being served have not been watered down . . . not a simple 'litmus' test

 

[klaus]

I am quite happy with the rough calculation the gravity measurements provides, if anything the taste suggests more strength than my calculations.

Anyway, you might want to look on http://www.brouwland.com/en/, the company that supplies the Brewferm brand, they have a lot of stuff on their website. Select "Measuring / Lab" link - you find equipment there. Looking at the prices though I can understand why most homebrewers stick with the gravity method.

But do let us know what you produce in your experiments
Cheers!

 

[Moley]

Welcome to the forum, and apologies for any misunderstandings (we've exchanged PMs before Peter was let loose).

For most of our beer and cider making, measuring start and finish gravities and doing the sums or using the forum's calculators (top left) are quite sufficient for our needs.

For winemaking using ingredients with known sugar contents, more maths can be thrown at it to calculate gravities, compensate for volume changes or work out what additional sugras can be added to push the yeasts to their limits.

To get a rough idea of the alcohol content, supposing we are given a wine and know nothing of its making or haven't bothered to keep notes, there is something called a Vinometer which is available from homebrew shops.

These are small, cheap glass devices which work on a capillary principle, are notoriously inaccurate and tricky to read. Better results are obtained if you dilute your test sample 50% with water and then double the reading, but they are still unreliable.

To avoid spiked drinks, the only practical answer is vigilance.

 

[BigYin]

bearing in mind as well, that a spiked drink may well simply not mean a few shots of vodka added, but there are plenty of drugs out there that a drink can be spiked with which will render the drinker almost unconscious - short of lab tests, I doubt very much any single test paper or piece of gear could detect more than the single thing it was designed to test - e.g. alcohol ...

 

[pe1850]

Thank you for your kind replies, you've opened up several paths for my meanderings. Ebulliometer eh? Thankfully I haven't sent up my Christmas list yet. I've added a gas chromatograph as well, and a Pathologist with big, er, ideas. I will keep you posted.
Whilst it is the holiday season there is one other, small thing troubling me. In some brewing recipes quantities are given in terms of flat teaspoons, and, even though I've searched the web, I can't find one anywhere.