Fresher Beer

[Rhyno]

This is worth a quick read

http://www.bbc.co.uk/news/science-environment-13067547

Basically talks about the initial ph value of your beer and how that changes the shelf life of beer, and also to keep your beer cool to increase it's life as well, wonder how much it cost them to figure that one out!

[Ralph]

Or you can just keep it cold...

 

On the dropping of pH tho... how would one achieve this and what sort of pH might they be talking. I have easy access to food grade acids such as citric and ascorbic... but these will add fruity flavours to the beer if in there at much of a concentration. Could easily add some acetic acid... but that is probably a flavour that most people are trying to avoid in their brewing process!!

[Rhyno]

Yeah it would off been nice for them to say what levels they had dropped them to, to view the attached pdf costs $35. Can't say I'm that interested in it to fork out that much!

[James Lawson]

If you're interested, I have access to academic articles, and can email this to you.

[Rhyno]

Actually yeah, I would like to take a look if it is no trouble. Brace yourself for a friend invite so I can pm you my addy :)

[Ralph]

yup mee too. Have friend invited so I can give email address too.

[Ralph]

Thanks for the article James. To summarise

 

They adjust the pH of the beer by adding Lactic acid to the beer after fermentation but before aging.

 

For the storage experiments performed with pH-adjusted beer samples, brewing trials were carried out in a 20 hL pilot plant at Bitburger brewery. A standard 2-mash decoction procedure was used to produce Pilsner-type beers from 300 kg of barley malt and 325 g of hop. Wort was boiled for 70 min at 100 _C and, then, fermented at

10.5 _C. Filled storage containers were 50 L barrels. The final beer samples were adjusted to pH 4.4, 4.3, and 4.2, respectively, by adding lactic acid and, then, stored 0, 30, 90, and 300 d at 20 _C in the dark.

 

The study showed distinct differences after aging for 90 days at 20 deg and even bigger differences after aging for a year at 20 deg C

 

So, if I have a pH meter on hand, I could adjust my beer down to a pH of 4.2 and get a beer that would keep longer. I am not sure what effect the lactic acid would have on the taste of the brew unless you were specifically trying for a “sour” beer. I wonder how much lactic acid you can add before you start to be able to taste it??

 

I guess you could also use the acidified malt and get a lower pH beer that would keep longer as well…

 

Interesting stuff.

 

[Rhyno]

Yeah very interesting, and I am sure raises a whole lot of questions in itself.

Like will it be beneficial for big beers that take a considerable amount of time to mature properly?

I guess only time and experimentation will tell

[Ralph]

The article talks specifically about changes in compounds derived from hops, especially the ones that cause the harsh lasting bitter notes of a beer that gets too old. The maturation of big beers with lots of malt etc is probably a different process and I have no idea what effect lower the pH might have on these reactions?? Having less of the pronounced bitterness from the hop compounds going off would still be a good thing in these bigger beers tho.

[Andrew]

I've found that oxidation takes hold long before any of these other factor take place so the chances are you beer will be oxidised long before the hops compounds start giving you problems. Unless you use old stinky, cheesy ones.

[Ralph]

All the testing in the article was analytical. As far as I can tell there was no sensory tasting at all. You might be right that the oxidation has wrecked other things long before this is noticeable. In their results they had beer that had been packaged in PET (plastic bottles) and aged for up to 4 years. Interestingly the hop compounds were less degraded in this packaging than in the glass or can... but I am sure that the beer would have tasted pretty bad with the amount of oxidation that must have gone on in the plastic bottles??

[James Lawson]

So I wonder what the effect of an acidic environment on oxidation is? And what is getting oxidised to produce the off flavours? Is it the complex carbohydrates or is it the proteins / peptides?. Or, for that matter, is it things like melanoidins and glycoproteins / glycated proteins? Shit I'm just starting to come to terms with the complexity of the biochemical soup.

I think I'd rather describe beer with a haiku than with biochemistry.

 

Aged four months

Alcohol whelms

Hallertau where are you?