It's a strange and misunderstood style of beer, which makes it all the more remarkable that Gose has had the kind of resurgence that it has!
Nearly extinct, both American and German breweries have saved this beer style, which can now be found on any number of tap lists and shelves. That's a wonderful thing, because it can be a fantastic beer. There is, however, a distinct challenge in brewing this beer: salt. Over- or under-spicing of any beer can present problems, but working with salt introduces higher stakes. Aim too high, and you end up with an undrinkable salt bomb. Aim too low, and you can't register the salt at all.
That we're doing this against the backdrop of a sour (is it?) beer, a low-ABV beer, and a spiced beer makes finding the right orchestration of flavors a genuine conundrum. Hopefully, this recipe will get you right in the ballpark, right out of the gate…and I know that's a mixed metaphor, but in a beer that's combining barley, wheat, coriander, salt, yeast, and lactobacillus, "mixed" seems to be par for the course.
If you want a jumping-off point for this style, start with Berliner Weisse. Both are low-ABV wheat-heavy beers with minimal hopping and tartness. Gose is a distinct animal, though. It has its own lengthy history, originating in small towns along the Gose river and produced in quantity in brew houses in Leipzig. The origin of the saltiness is a matter of some debate - some say that it was a result of slightly brackish well water, others that it was added for flavor - but in any case it's a defining feature of the style. Likewise, many Gose breweries in and around Leipzig don't add coriander, though I recommend it.
Where we (the Leipzigers and myself) part ways with American interpretations of the style is that theirs are far, far too sour. A large chunk of American Goses are just spiced Berliner Weisse. The sharp lactic acidity of Berliner Weisse is not consistent with the historical or modern versions of Gose brewed in Germany, and while I'm all for reinterpretations of styles I also think that sharp acidity distracts mightily from the subtler flavors that should be present in Gose. Subtle tartness enhances the flavors; blaring sourness overshadows them. Aim low. You can always make the beer more acidic; you can't take it out, once it's there!
There's no need to get clever with this recipe. The trick is in balancing the salt, coriander, and acidity - but more on that in a minute! We start with a simple four pounds each of Pilsner malt and Wheat malt. That'll do, for the grist. I'll occasionally bump up the ABV b about 0.5 percent by adding more wheat, which I speculate can make it easier to smooth out the specialty ingredient flavors, but I don't have proof of it - just anecdote.
Hopping is all at the top of the boil (only 15 minutes): add enough Hallertau to yield 15 IBUs.
Also into the boil will go your salt and your cracked coriander. I find that 0.4 ounces of pink Himalayan sea salt and 0.5 ounces of mortar-and-pestle cracked coriander do the job very, very well. The coriander doesn't need to be ground fine. I find the coarse cracked coriander to impart a softer, more-easily-controlled flavor. If you find that your salt expression is too high, you can adjust it downward in subsequent batches, but start here and see what you think. For my palate, it's just the right amount of noticeable salt and stops well short of being brackish.
In terms of yeast/fermenting agents, we have two options. First, you can ferment it out with Wyeast 1007 (German Ale) yeast and then adjust acidity with a straight addition of lactic acid, post-fermentation and pre-packaging. Second, you can pitch the German Ale yeast and a commercial Lactobacillus pitch at the same time at the start of fermentation, which should give you a touch of funk in the nose, some light acidity, but nowhere near what you'd find in a Berliner Weisse. The advantage of the second method is that it's unlikely to go too far with its acidity, so you can still adjust it upward with the lactic acid addition.
The advantage of the first method is that it's cheaper and simpler, and probably more-replicable. Your call! For what it's worth, I do either, depending on how much time I have on my hands and whether I happen to have any Lacto in the fridge. Results don't seem to vary that much (though I'm sure traditionalists are screaming at their computers right now that I'm cheating…oh well).
Mash as usual, perhaps with half a pound of rice hulls to prevent sticking, and run off into the kettle. Bring to a short boil - 15 minutes, total. Add your hops at the top of the boil, then the coriander and salt with ten minutes to go. After the boil, chill and pitch, fermenting at a steady 67F until the completion of fermentation. At that point, taste, and adjust with food-grade lactic acid, to taste. Package it up and carbonate to 2.75 volumes of CO2 - much like the Berliner, this should be a highly carbonated, "spritzy" beer!
You can ramp up your acidity if you want - it's your beer, after all - but I strongly recommend that you shoot for a balanced, nuanced interpretation. Too much salt definitely wrecks it. Too much acidity might wreck it. This won't be a clone of the American craft breweries' interpretations, but go to a good bottle shop and get yourself an authentic Leipziger Gose, and I think you'll find it's a great match!