Thursday, April 30, 2009

Brewing Sour Beer with Acid

So you wanted to brew a sour beer, you pitched the requisite microbes, waited a year or more for them to do their job, and and when you finally give it a taste it is just mildly tart. Pro-brewers take this opportunity to blend, but what if you don't have any acid beer to blend. Can you just take some acid and use it to sour up your ale? Wild Brews claims that you get a "harsh and medicinal" flavor if you just add food grade lactic acid (the main acid in sour beers), but it sounds to me like the author is talking about adding acid to a clean base beer (not to a beer that already has some acid and funk).

To answer some of these questions for myself I decided I would give acidifying a bottle of the Temptation clone I brewed 18 months ago that never got sour enough.

88% Lactic Acid - Lactic acid makes up between .18%-.52% in Gueuze (according to Wild Brews). This would work out to about 2.4 oz of this lactic acid in 5 gallons to get .3% lactic acid. A few drops in a small sample gave a classic sour twang, but there was also a hint of butteriness. I wonder if they use pediococcus in the production and some diacetyl makes it in. If it is the diacetyl , then adding this acid early in the secondary fermentation to give the Brett time to deal with it would be a good idea. When I added enough to make the beer really sour there was a lingering aftertaste, but it was hard to put my finger on exactly what it was.

Sherry Vinegar (7% Acetic Acid) - Acetic acid makes up between .06%-.12% in Gueuze (again according to Wild Brews). This would work out to about 5.5 oz of this vinegar in 5 gallons to get .06% acetic acid. I don't like my sour beers to have too much acetic acid, but I found that the lactic acid tasted better when there was a touch of acetic acid to give it a bit more bite. Of course you could use distilled white vinegar if you don't want any other flavor contribution.

With the two "standard" sour beer acids out of the way I wanted to try some of the other acids available at the homebrew store.

Acid Blend (Malic, Tartaric, and Citric Acid) - Acid blend is granular and usually used to adjust the acidity of wine and mead. It took a rather large amount of this to get noticeable acidity and it never tasted quite right, sort of like sweet-tarts. In small amounts blended with the lactic/acetic blend it complements the other acids (sort of like a fruit lambic).

10% Phosphoric Acid - This is the acid in sodas and in the bottle almost smells like a Cocoa-Cola. The sourness is certainly potent, but the character just doesn't taste quite right (the sourness didn't linger like a sour beer).

I was impressed by the results enough that I'll be giving this a more formal (measured) try the next time I have a sour beer to bottle that isn't sour enough.


Seanywonton said...

Now that's interesting.
I tried dosing a slightly sour berlinner weisse with extra lactic one time, but I liked it more without the lactic acid addition so I left it alone.

No surprise the Phoshoric acid didn't taste right. I've heard that's one of the ingredients cola makers use to keep the cola from quenching your thirst, hence making you want to drink more of it.

What about tying different flavored vinegars for different effects? Like Umi plum vinegar or champaigne vinegar, etc.

The Mad Fermentationist (Mike) said...

I think this has more potential in bigger/funkier beers where there is enough going on to make up for the lack of complexity contributed by the acid.

I have long had the idea of using a decent (but not great) balsamic vinegar to punch up a Flanders Red. Any of the other vinegars could certainly make for an interesting flavor addition, I just went with sherry since that was the tasty one I had on hand. That said at ~1 oz/gallon I’m not sure how much of the complexity will come through from any vinegar.

Tim said...

Great experiment!

I would have suspected that there is no way to recreate the complexity created by lacto/pedio by simply adding acid but to "dial up" the acidity sounds like a decent idea. Also, you might not get the byproducts of lacto production that Brett would consume and turn into subtle complexities over time.

You mentioned acid beer for blending up top. I have been considering brewing one up but not too sure how to go about it. Make a lambic and wait three years?

As an aside, I really need to sign up for that BBB board now that I'm getting into brewing sour/funky beer.

The Mad Fermentationist (Mike) said...

I believe “acid beer” is not necessarily brewed as such, it is just a particularly sour batch/barrel that is reserved for blending. Something pale and moderate alcohol like a lambic would be best though as it could be added to any beer without adding much else to the flavor.

Agreed, I think adding the lactic acid earlier in fermentation would probably give better results, but it would make fine tuning the acidity much harder.

The BBB is great, and for the homebrew board you don’t even need to sign up (you can just type in a name and use the L/P of 1/2 to post).

Mike Evans said...
This comment has been removed by the author.
Mike Evans said...

Excellent posting Mike. Have had more interest recently in how sour beers differ from each other. My issue is learning which acid contributes to specific beers. My taste buds are a big fan of Monk's Sour Flemish, do you think most of sour comes from acetic acid?

It seems like there is a decent amount of residual sweetness in this beer. I also notice that its filtered. I assume they blend a younger non-brett beer at time of bottling.

The Mad Fermentationist (Mike) said...

To me Monk's Cafe is mostly lactic with a hint of acetic. There are not many beers out there with a huge acetic character, La Folie probably has the most, but some other Flanders Reds are up there as well.

It could either be a blend of a sour and a clean beer, or two sour beers one old one young. Either way it is pretty hard to replicate something like that at home outside of blending in the glass.

Brad said...

I once brewed a faux-Berliner Weisse by fermenting the beer with Kolsch yeast and adding food-grade lactic acid at kegging time. I don't have a dedicated set of plastic gear for wild bugs so I didn't want to risk cross-infections. (Aside: has anyone determined that this fear is nonsense?)

I've had limited exposure to real Berliner Weisse so I don't have much basis for comparison. The beer came out decent by my and others' standards. The perceived sourness seemed to fluctuate. By the end of the keg, though, the beer overall had lost some life.

Ron said...

I think a lot of smaller brewpubs that want to make a flanders red beer just chuck a bunch of lactic acid in the serving tank. I saw this on some forums on

I occasionally add a small amount of lactic acid to not sour enough 24 month fermented flanders reds and it works well. I'm talking a couple tablespoons in 5 gallons though.

People have won major homebrew competitions with soured only by post fermentation lactic acid, especially in the Berliner Weiss category.

All that said, I do whatever I can do get the flavors the natural way. Of course, I too have a temptation clone that's 6 months old that needs some more twang!

Chad Y. said...

Hey Mike,

Finally got around to reading this post after the mention of it on BBB homebrew boards. Uncanny similarity! I like the detailed info. I added 100ppm, 500ppm, 1000ppm, and 3000ppm to the standard worts to observe for the formation of Ethyl Lactate from 8 different strains of bretta, and also if it could be the "pineapple" aroma so sought after in an all bretta beers. I wasn't interested in making a sour beer as I think bretta beers should be clean with a slight identity from the funk and tartness. Anyways I'll compare back to what you found as this was a great write up!

Chad Y. said...

Oh yeah and I definitely agree to add the lactic acid earlier in the ferment to let the brettas do their thing as this could change the "edge" perceived from the straight addition, creating balance to the acidic ale.

Unknown said...

Is it me or was acidulated malt skipped in the experiment?

Yes I think not brewing with bugs because of a fear of cross-contamination is a little silly. How much does another carboy a hose and a racking cane cost?
If you are cheap like me you will just use your same old equipment and make sure you clean super thoroughly afterward.
Much love from Philly

The Mad Fermentationist (Mike) said...

The idea of this was really to adjust the acidity of a sour beer after fermentation, something that acid malt really isn't good for.

I've never had great luck with acid malt, it seems to me that if you add enough to make a beer really sour it will drop the pH of the mash too much. Has anyone had good luck with it?

Brad said...

Damn Mike, you sure do get a lot of spam comments here... wuddup with that?

The Mad Fermentationist (Mike) said...

It had been getting better for awhile, but that's what I get for allowing anonymous comments, and not having one of those word verification things or comment moderation... hopefully the ease of posting is worth the bit of effort on my part to delete spam.

Brad said...

No captcha?

I guess as long as you catch them quickly, no major harm. Although it does mean people who subscribe to the comments get to see the spam too.

The Mad Fermentationist (Mike) said...

Just switched the captcha on (I hadn't been considering comment subscribers), hopefully it isn't too annoying (and it actually prevents the spam).

Larkin said...

This is exactly what I'm about to work on: dialing up the sour on a Flanders Red that's got plenty of complexity but not enough punch. Here's my question, though: did you add the acid AFTER you carbonated, or before? I'm bad at guessing how a beer will turn out before it's chilled and carbed, so I'd ideally like to adjust it from there, not in advance.

The Mad Fermentationist (Mike) said...

In this case I was blending the acids into a bottle of sour beer in the glass. I have added lactic acid to taste before bottling for my Honey Wheat sour. Adding it post carbonation is really only practical if you keg. You could chill the beer and carbonate with a carb-cap to do your tests, then scale up before bottling. Good luck!

Larkin said...

I ended up adding a full bottle (4oz, I think? The same bottle pictured above) of 88% lactic acid to about 4 gallons of uncarbonated Flanders Red. The result was great - not too tart, not medicinal, just perfect.

When I pressurized the keg, though, the additional bite from the carbonic acid made the final product so tart that it was undrinkable. I blended back with a gallon of amber ale that I happened to have on hand and, now, am really happy with my finished beer; its similar to the American Wilds from Russian River, and still has no medicinal after-taste from the added lactic.

The beer I used sat in a fermenter for eight months before I kegged and bottled, but I intend to keep the bottles for at least a year before I start drinking them in earnest. I'll check back in a few months to report how the bottles have aged.

The Mad Fermentationist (Mike) said...

Sounds really good, glad the lactic acid worked out. Did the beer have Brett and bacteria in it as well and just did not soured as much as you wanted?

Ryan said...

I did a Brown Sour a couple months ago from a proven recipe where I've tasted the end product. I altered my fermentation methods a little compared to what it called for just to be a little different by tossing lacto to it and incubating at 95F for about 7 days instead of just tossing roesalare to it. After the initial incubation of 7 days and allowing it to cool a day, and tossed roesalare to it. My idea was to hopefully add a little more sour to it by allowing lacto to take it down a bit before the roesalare.

After about a month into it, I was curious of the taste and it was very MEDICINAL/CHEMICAL tasting. It really made me nervous that I might have to dump it. I tasted it again about 2-3 months into it now and its definitely not like it was, but some of that medicinal/chemical taste is still there.

I'm curious if you've learned anything further about what these flavors are that I'm talking about. Is it just part of the process that it has to go through, or was it in my methods of incubation at first? I do know that my friend I brewed this with threw roesalare to it from the get-go. His doesn't taste like mine with the bad flavors, but his is also not NEARLY as flavorful in any way. This was a 10 gallon batch that we split, so the issue was not in the brewing process itself. Thanks for any information you can give me/us on this medicinal/chemical taste that I'm talking about.

The Mad Fermentationist (Mike) said...

Any idea what the pH of the beer was when you pitched the Roeselare? If the Lacto lowered the pH below ~3.4-3.5 (which wouldn't be surprising given the time and temperature) it could cause a very unhappy primary fermentation by the Saccharomyces in the blend. That is my big objection to "pre-souring," it can work, but takes careful control and monitoring. A friend had similar flavor develop in a Berliner weisse that he allowed to sour before pitching brewer's yeast. There is a chance the Brett could soften the flavors with time, but I wouldn't guarantee it.

Best of luck!

Ryan said...

Unfortunately, I don't know what the PH was. I'm sure it dropped pretty low considering how it cooked with lactobacillus. Thanks for yoru answer. I'll bet you are correct about the Sacc not being happy. There are some yeasts like 1007 that can withstand low PH and they are happy regardless. Right now there is a pelicle forming and the last taste did tell me that it was getting much more mild. I'm hoping time and brett fixes it.

Unknown said...

Hi Mike

I can't wait for your book to come out.

I added a bit too much lactic acid in my Gose. Is there anything to be done to counteract the lactic acid?

The Mad Fermentationist (Mike) said...

You could add baking soda or chalk to raise the pH, but I'm not sure that either will really improve the flavor. Your est option is to blend the gose with another beer or another batch to dilute the acid.

Next time, do a few measured blends to figure out the approximate amount of acid you want to add. Carbonating the sample with a Carbonator Cap is a good idea to get a truer impression of the acidity.

Good luck!

Anonymous said...

Some of your math seems to me to be a touch off...would 2.4oz of 88% lactic added to 5 gallons of beer be .003% lactic acid? Formula of 640 oz. (5 gallons) divided by the amount of lactic acid in 2.4 oz (2.1 oz? I guess I could be wrong but...On a more positive note, I think this is some good experimentation and research, thanks for posting and keep up the experiments!! Prosit!!!

The Mad Fermentationist (Mike) said...

Nope... 2.1/640 = .0033 = .33%

64 is 10% of 640, 64/640 = .10 (you multiply by 100 to convert a decimal to a percentage).


Anonymous said...

Hi Mike,

Big fan of the blog, apologies for the zombie comment; I recently dug up a bottle of Golden Strong I had dosed with Orval dregs at bottling, which after a few years had pronounced Brett aroma but was flabby and wishy-washy in terms of flavour. After 4 years or longer, I decided it wouldn't be getting better, so I experimented.

A couple of drops of apple cider vinegar in a 250ml glass brightened the flavour AND aroma up like POW! Not noticeable in terms of distinct vinegar flavour or aroma, but totally tightened and brightened the beer. The next glass copped white wine vinegar, and was different, but just as improved. The final glass got both vinegars (a drop of each) and was very, very good. A quick google and I was here, on a blog I already read regularly, reaffirming what I had just learned.

Not sure where I can use this info in terms of bettering my brewing, but it's nice to know that acetic acid (in the form of less refined vinegars) can potentially move a "meh" Brett beer to something worth drinking.


Noiz Boy said...

I tried going by a formula like you did and ended up with a bit of a nasty mess. BUT recently I was aiming for a tart beer ala Aunt Sally and didn't have the time to experiment with kettle souring so I gave it a shot again and it was a hit.

The first time I had a lot of others coments. The acidity was very one dimensional and boardered on "chemical". What I changed was to use a mixture of acid blend and lactic acid. It helps that this beer had citrusy hops so for other styles YMMV. I only brought the word down to 3.8. 50g + 11.5g, mixed with 500 ml of water then added to the wort pre boil. It really brought out a grapefruit note that is also part of the Citra and Zythos hops.

I think that also it's a plus to "cook" the acid with the word to help things meld together.