Math Help Needed

[Gillman]

There are some good numbers people on the board and can one provide help? On a historical beer blog, a 19th century analysis was reported in which two samples of Guinness XX Porter were analysed, each showing 3.6 parts acetic acid per 1000 parts of beer. See the current post, here:

www.barclayperkins.blogspot.com

If I wanted to add vinegar to a bottle of 12 ounces of porter to try to equate to that amount, how much would I have to add, factoring also that vinegar is (I believe) sold in diluted form. Say I wanted to add white vinegar or wine vinegar, how much should I add to a 12 oz. bottle? Thanks for all help.

Gary

[barturtle]

Hmmm. table vinegar is only 4-8% acetic acid by mass (and it's ever so slightly heavier than water by volume, but probably close enough that for this application was can go ahead and say it's 6% by volume for our uses)

You want to come up with 3.6 parts per thousand.

Working in mL: 355ml (typically what's listed on the side of a 12oz can)

1.3ml of acetic acid into 355ml= 3.6 parts per 1000

23ml of a 6% acetic solution=1.38ml of acetic acid.

So about 23ml of table vinegar.

[Gillman]

Thanks Timothy!! Will report on results.

Gary

[Gillman]

I added 23 ml Italian wine vinegar to a bottle of Jose Marti porter. This is a sweetish, rich porter, I would doubt the attenuation is beyond what was typical of Guinness in the 1800's. The ABV (8%) is higher than that of Guinness Porter then, but let's ignore that.

I figured the wine vinegar would get closer to acetic acid produced during a beer ferment than your usual white vinegar, but anyway they smelled quite similar. The vinegar was a 6% solution, so exactly on the mark in terms of Timothy's calculations.

It actually wasn't bad at all: the acetic hit delivers a racy edge that complemented the rich malt. The Jose Marti probably would need an extra hit of hops to get closer to the Guinness Porter of the 1800's, and probably would taste better for it, but it's still pretty good. Sour-sweet, as a lot of old tasting notes say for porter.

It would be interesting to do a blind taste test amongst porter fans, one with and one without the acid, and see which they like. It's pretty sour but I still like it.

Gary

[Gillman]

When Libby came home, I asked her to take a sip, saying, I won't say what this is, just tell me what you think. She said, it reminds me of kriek (a Belgian ale noted for its sour, fruity taste). This suggests to me that kriek truly is a survival of times past, times when all ales tasted somewhat sour.

Gary

[IronHead]

When Libby came home, I asked her to take a sip, saying, I won't say what this is, just tell me what you think. She said, it reminds me of kriek (a Belgian ale noted for its sour, fruity taste). This suggests to me that kriek truly is a survival of times past, times when all ales tasted somewhat sour.

Gary

[Gillman]

I do know that kriek means cherry and is a traditional style of sour ale in Belgium. But it is another thing to get an independent confirmation so to speak of its historical nature. Guinness in the 1800's had a measure of aged beer (thus somewhat acetic or lactic one assumes) added to form the final blend. But again, how sour was it really? It is only these 1800's technical analyses that can assist to show us, or confirm, what the actual taste was, IMO.

Gary

[craigthom]

"Flavoring" vinegars, like wine and rice, generally have a lower percentage of acetic acid. It pobably doesn't matter in this application, but it does when you are canning stuff.

[Gillman]

I'm going to try it again, with white vinegar. There has been further discussion (in the comments section) in the link I posted about the calculations. More soon.

Gary

[barturtle]

Glad I could be of help, Gary.

I probably would have tried the white vinegar first, to get the cleanest acetic acid flavor.

I wonder how close it would be with Guinness Foreign Export Stout?

[Gillman]

Good question about the Guinness FES. The latter has a certain tartness, but not markedly so, and 23 ml vinegar added to a bottle of similar stout (except richer due probably mostly to lower attenuation) resulted in a very different taste, much more acid. Also, all Guinness today I understand uses some type of food-grade acid to impart the "aged" element: apparently, long-stored beer is no longer used. So the taste of the acid may be somewhat different too.

We can try this together the next time I see you, Timothy, maybe at KBF in Bardstown. Thanks again for helping.

Gary