Berliner Weisse - Sour Mash

Berliner Weisse - Sour Mash

The elusive sour mash method of creating a naturally sour beer is something you will rarely find a good write up on; everyone does it differently or doesn't give all the details. Here I will try to alleviate your struggles by walking you through the unique and smelly experiment known as the sour mash berliner weisse. I hope this will inspire you to try one of your own, it really turned out great!

Generally speaking, there are two main ways to create a traditional sour beer; sour mash or post-fermentation souring. The latter and easier of the two methods requires the beer to age longer and in my book is just too easy! The sour mash method is more interesting and stinkier but produces a great tasting sour beer in half the time. If you wanted to go the easy route, like many breweries as of 2018 who are more concerned with profit than process, you could use a lot of acidulated malt or just straight up add lactic acid in to your final product - but that would be cheating.
I've read a lot about sour mashes and from what I can tell, everyone does things differently, this shit is free form! From souring for 24 hours to 72, only souring part of the mash or simply using acidulated malt to achieve the sourness. From the history of this beer that I read it sounds like a full sour mash is what the Germans did, so that's what I will shoot for.

Style & Target
Berliner Weisse
5 gallons 3.2% abv

3 lbs US 2-row (yes, I prefer it to pilsen)
3 lbs white wheat malt
4 oz aromatic malt
4 oz dextrine malt
4 oz crystal 120 L
.5 oz Tettnang (15 minutes)
Safale #04
pint of un-milled 2-row
2 lbs strawberries
1 lemon
1 lb raspberries
*Recipe calculated with BeerSmith 2.0 - The best brewing software around*

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Regular brewday stuff plus a method to keep your sour mash warm for 72 hours. I used my 10 gallon cooler mash tun, a cheap repti-heater and many blankets. I had to add warm water twice, which I will elaborate on later.

*Sour Mash Procedure*
Start off like any other mash, mill your grain (set aside an additional pint of 2-row, do not grind it), bring your water to temperature and mash in.

Mash target temperature is 148 F for 45 minutes. Instead of draining the tun let it cool to 125 (this may take a while!) then toss in the pint of grains. The grains contain the bacteria we want making lactose in our mash. Since the lactobacillus and it's friends don't survive too well over 125F, it is very important that you don't add that unmilled grain until after or you will hamstring their ability to reproduce and survive.

Be aware that oxygen is your enemy here, it will feed the bacteria, like acetobacter, in your mash that can create vinegar. So, after you cool the mash then pitch the grain, flood the container with CO2 if possible and cover the top of the grain bed as best you can with plastic wrap - so that it is literally touching the mash. The less oxygen the better.

Keep your mash between 100 and 120 F so the lactobacillus can do it's job better and faster than the other bugs that will try to take hold. I did this with a very low power repti-heater (only get's up to 90 F) and many blankets. This slowed the cooling process of the mash in the cooler drastically. When the temperature dropped to 100 F, I added a quart of 120 F water and subtracted it from the total amount of sparge water I would need later. I did this only 2-3 times and was both pleased and amazed with how well the cooler holds its temperature.

Small scoop of the horrible smelling sour mash

The Goal here is to have a mash that smells as much like plain Greek yogurt as you can get; sour and fruity. Unfortunately with this equipment it's very unlikely to smell that clean. Even with CO2 flooding and fairly good temperature management this mash still smelled a bit like some yogurt that spent all of 20 minutes in someone's stomach before being wretched up into a bucket. That horrible idea aside, it tastes better than it smells (yes you should taste everything!) but not much... it's really quite gross - but fear not, the end result is spectacular and worth a stinky spare bedroom for a few days!

*Sparge & Brewing Procedure*
Things go back to normal from here. Bring your sparge water up to temperature and get to work like any other brewday! My sparge was around 4.25 gallons.

Brewing will be even easier than average since you will only need to do a 15 minute boil. This being said, next time I might go for a 30 minute boil to make sure all the bacteria is killed since I'm pretty sure some survived my first try. It wasn't a big deal but could create bottle bombs if you're not careful.

The hop schedule is very light, just 0.5 oz of Tettnang for 15 minutes.

From there you will cool the wort, pitch ale yeast and treat this like any other beer. I gave it two weeks in primary, like most of my beers.

After that you should rack it onto some fruit. For this experiment I split the batch in two, with half on strawberries and a lemon and the other half on raspberries. The fruit could definitely be doubled so keep that in mind as well if you give this recipe a go.

After two weeks on the fruit there was a nice pellicle, so the lacto-bacteria was probably not dead but don't be afraid of it - it's fine - just try to keep the pellicle out of your final transfer.

I bottled it up and two weeks later enjoyed the hell out of it! Barely traceable butyric aroma and after another week conditionating it was gone! Five weeks is pretty damn good for a sour / berliner if you ask me. The raspberry color came through but the strawberry batch remainder a pale straw color. There is a beautiful and tall initial head that dwindles to a nice thin layer as the beer warms and you continue to sip. It is sour to the point of pucker but not as overwhelming acidic as some New England or Florida sours tend to be. This was a really great first go, the fruit is very subtle but the tartness is well balanced by the mild fruit sweetness left behind.

I hope you enjoy this recipe as much as I did and although it can get pretty rank it is worth the effort. Soon I will try doing it the easier way and add some lactobacillus into primary and forego the sour mash all together. We'll see which is better in the long run - taste-wise and effort-wise.

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