Gose-lactic or citric acid

[bklynbrewer]

I am going to be making a gose pretty soon and will sour it with acid, not lacto. Does it matter if I use lactic or citric acid? What differences are there between the two?

[brewinhard]

Lactic acid would be more traditional yet possibly one-dimensional. By adding a little citric acid in addition to the lactic acid you may be able to achieve a more complex sourness. Pour a glass of a typical wheat beer and dose it to taste with the lactic and citric acid to see how the two compare and contrast.

If you are not using lactobacillus, then why not include some acid malt in your grain bill if brewing all grain?

[mabrungard]

These soured beers are almost always characterized by their predominantly lactate ion content. However, there is also a very low acetate content. So if you are performing a 'natural' souring where you have pitched something like the handful of grain in wort method, then you will typically produce a small amount of brettanomyces which will produce acetic acid. Keeping the souring wort isolated from oxygen will help prevent the Brett from producing too much acetic acid.

Along that same line, if your soured beer does not have much depth or the sourness is one-dimensional, then adding distilled vinegar to the finished beer can help add depth. It takes very little, so don't go adding a lot or your beer is ruined.

I still have to work out the dosage.

[brewinhard]

I have never experienced any acetic acid notes either in aroma or flavor in commercial goses. The Leipzinger version from Germany in fact was surprisingly, mildly tart at best (if at all, really). When I have brewed these in the past, I have always stepped up a large starter of lacto and let it ride at hot temps prior to pitching my ale strain much in the same fashion as a typical Berliner weisse.

I would be cautious when performing a sour mash as they can easily get away from you and produce excessive enteric and butyric off-flavors if exposed to too much oxygen. The best way to perform these is in a corny keg where one can flush out any oxygen and maintain a CO2 blanket above the mash.

The second best way is to make a small starter (i.e. 2L) with DME (low gravity - 1.020 or so) and inoculate it with a handful of crushed base malt (acid malt can be used too). Let it ferment out in a closed environment with an airlock at hot temps for a week or so before tasting to see what the results were. If things look, smell, and taste good, then decant and pitch your starter culture into your whole batch.

Just some ideas to think about when tackling this interesting style....

[mabrungard]

Using the hand-full of malt method for creating a lacto starter, can and should produce slight butyric or enteric aromas, even when in an anaerobic environment. However without oxygen, they are rapidly overwhelmed and their flavor and aroma products consumed by the on-going bacterial competition. The acidification will generally produce a near-monoculture of lacto.

As an experiment, I created a malt-based lacto starter in a foil covered flask with 100F heating. That worked out very well. I then created my Berliner wort and transferred that to a standard 5 gal corny keg and added the starter. Even though the wort filled the keg to within a 1/4 inch, lacto does not produce a head during its fermentation and there were no problems. I just vented the keg daily. Of course, the keg was also heated to almost 100F. This technique worked very well and will become my standard. That soured wort was then boiled for an hour. By the way, when poured from the keg into the kettle, the wort produced a HUGE and dense head.

By the way, I finished the calculations for adding an appropriate level of acetic acid to Berliner Weisse. Using the typically available 5% distilled vinegar from the grocery store, it turns out that it takes between 6 and 12 mL of distilled vinegar per liter of beer to produce the appropriate level of acetic acid found in great BW's. I checked the effect of the 6 mL/L addition by adding it to RO water and I could just barely taste it. So, that lower end dose has no potential of ruining your beer. You should evaluate if a higher dosage meets your expectation by dosing in a glass of beer...before you dose a whole keg of beer.

[bklynbrewer]

Those are both incredibly detailed and highly precise suggestions that I could definitely repeat, thanks for the ideas.

The most recent issue of Zymurgy (March/April) has a Gose recipe on pg 21 that leaves out a lacto addition and does the acid taste with acid only. But both of you suggested using a lacto culture. Do you get a more well-rounded "realistic" flavor using the yeast? Jamil mentioned that on the Berliner Weisse show, so is this a similar idea?

[mabrungard]

I definitely did not prefer the Berliner Weisses that Wyeast brought to the past two AHA conventions. They were soured with one of their cultures and they just seemed too one-dimensionally lactic. They were still fine beers, just one-dimensional.

I recall reading someone also commenting that when the souring was dirtied with those other organisms, the flavor became much more comparable to the BWs that that person said they had tasted in Germany.

Even at 100F, it did take a week for that starter to go through its funky stages and finally settle into a smooth lactic aroma and sourness. When I pitched that lacto starter into the 5 gal batch, it also went through funky stages. I was picking up some 'appetizing' sewer aromas at one point, but it did clean up in the keg. When that soured wort was boiled, it had wonderful fruity notes. By the way, I took both the starter and 5 gal of wort to a 3.1 pH. I didn't use the German Ale yeast 1007, but used US-05 and it took off after about 6 hours. So that dry yeast seems unphased by this very low pH. The 1007 is reputed to be very acid tolerant, but I wasn't willing to pay double for 1007 when compared to US-05 at my LHBS. The relatively clean nature of US-05 works well in this style.