Testing beer for "lightstruck" 3-methylbut-2-ene-1-thiol

Taste it

 

ditto

 

As others have stated, the best way to test for the presence of 3-methyl-2-butene-1-thiol in beer is to taste it. If you perceive a skunky aroma/flavors then 3-methyl-2-butene-1-thiol is present.

Below are some details on how 3-methyl-2-butene-1-thiol is formed:

“So where does it come from? Unfortunately, the source is the main ingredient that gives beer great taste- hops. In brewing, the blossoms of the hops flower are added to balance the sweet taste produced by the malt. Among a number of compounds present in hops is iso-humulone. Upon exposure to light, iso-humulone is hydrolyzed producing an active electrophile. Nucleophilic thiols present in the brew then react with the electrophilic fragment to give the odorous 3-methyl-2-butene-1-thiol.”

Cheers!

 

I think you were simply quoting some other source, but isohumulone isn't present in hops. (Or if it is, it's at some trace level that I've never seen mentioned.) It's the product of the isomerization of humulone, which normally happens in the boil/whirpool/hopstand. I think heat and water (or wort) are both required.

 

The below paragraph in quotes is indeed quoted from an on-line source:

“So where does it come from? Unfortunately, the source is the main ingredient that gives beer great taste- hops. In brewing, the blossoms of the hops flower are added to balance the sweet taste produced by the malt. Among a number of compounds present in hops is iso-humulone. Upon exposure to light, iso-humulone is hydrolyzed producing an active electrophile. Nucleophilic thiols present in the brew then react with the electrophilic fragment to give the odorous 3-methyl-2-butene-1-thiol.”

The compound of iso-humulone is present in beer via boiling hops during the beer making process. Iso-humulone is the isomerized form of humulone (humulone is present in hops; it is an alpha acid).

Cheers!

 

Spend $30,000-40,000 and get yourself a gas chromatograph with a single quadrupole mass spectrometer and purified 3-methylbut-2-ene-1-thiol (to build a standard curve from) if you want to be able to semi-quantitatively (through the use of internal standards) assess 3-methylbut-2-ene-1-thiol levels.

An alternative would be to buy food grade 3-methylbut-2-ene-1-thiol and dose it into beers slowly increasing the ppm level until you hit a detectable threshold. Then calibrate your self with known amounts via tasting to be able to be your own detector.

Alternatively you could buy a corona and dilute it with bud light to develop different ppm levels of 3-methylbut-2-ene-1-thiol and calibrate your pallette.

 

In other words...there is no inexpensive instrumentation currently available, other than your taste-buds.

 

isn't corona now brewed with tetra hops to prevent skunking?

 

I think Miller uses them. AFAIK Corona either considers the skunked flavor to be a feature rather than a fault, or just doesn't care.

Edit: I think I might be wrong about Corona.

 

Hmm.... not sure. A friend left some in the fridge and when my mom was visiting last week she drank one and complained about how awful and skunky it was.

 

if you are really serious about knowing the concentration of a particular chemical in a liquid, you can contact a testing lab. a food testing lab will probably be able to quote you a price fairly easily. other labs with a GC can probably do it if they are interested but you are going to pay. and they might just subcontract anyway.

you can find this data in parts per billion if you have enough money. you can test for anything if you have the money and the time.

or, as noted, taste it!
Cheers.

 

I really don't want my coronas to be NON-skunky. Once you get used to a taste, you expect it. That's why you add the lime.

(this post may contain bullshit and / or non-truths)

 

I hate Corona beer