Sour beers seem to be all the rage among craft beer drinkers at the moment.
They are a unique and flavorful addition to any craft brewer’s repertoire. With their tangy, tart, and sometimes fruity taste, they are a perfect contrast to the usual bitterness of traditional beers.
Beer geeks will love the extra layers of flavor that a sour beer offers, while those drinkers who aren’t too keen on the taste of beer like the fact it doesn’t taste like your typical ale.
Unfortunately, sour beers also tend to be one of the most expensive beers in the bar. Brewing sour beer is a bit different from traditional beer brewing and requires a few extra steps to achieve the desired tart flavor.
For many homebrewers, especially beginners, brewing a sour beer is a great unknown and can be a very scary risk, what with all the hype of using the wild yeasts and bacteria spoiling every future non-sour beer they brew.
Many more experienced homebrewers would argue that by introducing wild yeast and bacteria to your homebrew setup, you will have to then replace all of your brewing equipment.
Any leftover troublesome bacteria will increase the risk of every IPA or Pale Ale you brew in the future turning into a hopped-up lambic beer.
However, while it is a risk, it’s not quite as big a risk as many would have you believe.
Let’s take a look at a few sour beer recipes you can make at home without having to replace your entire homebrew setup or invest in backup equipment.
I’ll warn you, though, patience is key when brewing a sour beer. Plan on leaving this beer in secondary fermentation for at least six months. If you don’t want to wait, then this is not the beer for you!
What Is a Sour Beer?
Although American brewers only seem to have jumped on the sour beer bandwagon in the last decade or so, sour beers are actually the oldest style of beer in the world.
In fact, all beers would be somewhat sour in taste before pasteurization and sterilization techniques were better understood.
The sour beers of today are tart-tasting on purpose and produced with wild bacteria and yeast, compared to the more familiar styles of beer made in more sterile environments with cultivated yeast strains.
But those wild organisms (remember yeast is strictly speaking a fungus) can give a finished beer more enticing flavors. Sour beers come in a huge range of styles which can run from extremely, mouth-puckeringly sour to a funky, fruity, lighter taste.
Some of the most famous styles of sour originate from Belgium, where the sour beers are often aged in oak barrels allowing the beer more time to breathe and allowing the microorganisms the opportunity to build small communities.
There are even some Belgian sour beers that use wild yeasts and bacteria found in the air of their local area.
What Makes a Beer Sour?
Bacteria is the active ingredient that gives a sour beer that distinctive sour taste, while wild yeast can add a funky or earthy quality.
Modern sour beer styles are primarily created using two types of bacteria and one type of wild yeast.
The first bacteria is one that turns sugars into lactic acid.
Lactic acid is the same acid that makes yogurts have that slightly sour taste and is also one found in the human body which turns your muscles “sour” after a workout.
Lactic acid lowers the pH of the beer rather quickly (often within 24-48 hours) giving the beer a sour yet clean taste.
This bacteria is normally the primary souring agent in Geman styles of sour beers such as Berliner Weisse and Gose.
A bacteria from the same family as Lactobacillus, and often referred to as Pedio, it’s the other common lactic acid bacteria used in the souring of sour beers.
It is also used in other culinary procedures such as the acidification of sauerkraut and traditional air-dried sausages.
Unlike Lacto, the Pedio bacteria takes a long aging time to start the dramatic lowering of the pH of the beer which offers the advantage of allowing the primary yeast used to complete its fermentation process before the drop in pH occurs.
The main drawback to using Pedio bacteria in acidifying your beer is the large concentration of diacetyl which can occur, leaving a buttery flavor, almost popcorn-like, to a batch of beer.
Using Brett yeast in sour base beers which have been pitched with Pedio can help eliminate the diacetyl over time. Some younger sour beers can often taste like movie theatre popcorn, but if aged, they will lose much of that unwanted diacetyl.
The other major difference between Lactobacillus bacteria and Pedio is the actual type of sourness they leave a beer with. Lacto produces a clean sour taste, while Pedio can often produce other funkier flavors and aromas resulting in a harsher sour taste.
But, on the plus side, Pedio bacteria does give wild yeast more fuel for lactic acid production.
Pedio is the bacteria responsible for the sourness in most Belgian sour beers such as Lambics or Flanders Reds.
Often simply referred to as Brett, Brettanomyces is sometimes called a genius of a yeast and is the primary yeast (not bacteria as many brewers falsely believe) used in sour beer production.
Different strains and species of the Brett yeast can offer specific flavors, aromas, esters, and phenols to the beer ranging from a pineapple fruitiness to hay, horse blanket, or acrid smoke.
A beer’s character will also be influenced by the acids and alcohols which combine with the esters during the fermentation process.
However, Brett doesn’t contribute too much in the way of acidity to your beers, that’s the role of the bacteria. An exception to this occurs when a large amount of oxygen is available to the yeast which causes the Brett to produce acetic acid adding a vinegar-like sourness to the resulting brew.
Although Brett has a reputation as a beer ruiner, adding poopy and Band-Aid flavors to a beer, at its best and when used correctly it can add a balancing layer of earthiness to sour ale.
Also known as brewers yeast, this is not traditionally a souring agent as it is used in the fermenting of all clean, regular beers, but it can also be used in the production of sours.
Basically, the ordinary brewer’s yeast does the majority of the runt work in fermentation by reducing the gravity of the beer and producing the alcohol.
A fast-working, highly IBU-tolerant yeast, it acts as a base yeast protecting the wort and setting the stage for a traditional slow-moving fermentation with wild yeasts and bacteria.
Different Methods to Make a Beer Sour
Just as there are many different styles of sour beer, there are also a variety of different ways in which you can brew a sour beer.
Some of the more popular ways of brewing a sour beer include:
- Kettle souring – the fastest and easiest, this is recommended for most homebrewers.
- Mash souring – more complex with less reliable results sometimes.
- Secondary barrel aging, souring, and mixed fermentations – the longest process.
- Primary fermentation souring – another quick method for homebrewers where bacteria is heated to a temperature where yeasts can not survive in the early stages of fermentation.
Whatever method you choose, I would recommend having some secondary equipment or being willing to throw the primary fermenter away after brewing your sour beer.
Kettle souring is probably the least dangerous method with the lowest risk of cross-contamination of future brews, as you kill the bacteria at the boil.
What Hops Are Used in a Sour Beer?
When it comes to brewing the best sour beers, you really don’t want too much bitterness – bitter and sour isn’t a combination that goes together too well.
The real problem is that you can’t have a beer without hops, and the acids present in hops help lower the pH of the beer, so producing the acidity levels and sourness you are looking for.
The Secret Is To Use Aged Hops!
The Belgian sour beer brewers will commonly use hops that have been aged for one to three years in warmer environments.
This may go against everything you have ever been told about the use of hops in beer, but with a sour ale, we are not primarily looking for a hoppy beer. Instead, the hops should be a flavor contributor by helping to lower the pH of the wort, thereby enabling the bacteria to thrive and produce more of that sourness-creating lactic acid.
Hops, when being aged, will at first take on a funky smell before gaining a cheesy aroma. Eventually, they should lose all aroma in addition to the sharper alpha acid bitterness.
Instead, the hops will gain a subtler and smoother bitterness from the beta acids as the hops react with oxygen.
if you can’t find any aged hops, or you simply refuse to age some of your best hops, try to find some low alpha acid hops which can help with the alpha/beta balance in the beer.
But most of us have some old hops that have been forgotten about and maybe left in the freezer for the last 5 years or so. Simply take them out a couple of weeks before your beer brew day, and leave them in a paper bag on top of the refrigerator to age.
They may only get to that funky, cheesy-smelling stage, but that should be enough to have lost the harsh bitterness of the alpha acids.
Brewing Your Own Sour Beer – The Recipes
Now we have looked at the different brewing methods and ingredients that can make a beer sour, let’s take a look at a couple of recipes you can try at home.
One is an all-grain, kettle sour recipe that is ideal for the home brewer and takes much less time than the traditional 6- 12 months of fermentation for a typical sour ale brew.
The second recipe is a basic sour ale recipe that uses the primary fermentation process of souring.
You could always pour over 4 – 6 pounds of fruit in the secondary fermentation stage if you wanted to make a Sour fruit Beer – dark cherries would be my recommendation.
Kettle Sour Beer Recipe
- Makes 5.5 gallons at 4.6% ABV
- 5 lbs. Pilsner Malt
- 4 lbs. Wheat Malt
- 0.5 oz. Saaz hops (60 min)
- 1 pack Omega OYL605 Lactobacillus Blend
- 1 pack White Labs WLP001 California Ale
- Mash the grains for 60 minutes with 3 gallons of water at 161ºF, to reach a mash temperature of 150º.,
- Sparge with 8.5 gallons of water at 168ºF to collect 8 gallons of wort.
- Boil for 10 minutes and chill to 95ºF.
- Add the Lactobacillus blend to the kettle, purge/blanket with cO2, and seal up the kettle with plastic wrap and tin foil. Hook up heaters as needed to keep the kettle in the 90-100ºF range. Test pH after 12-24 hours. Once desired pH has reached the 3.2 to 3.6 range, unhook everything and proceed to boil.
- Boil for 90 minutes, adding ingredients as indicated. At the end of the boil, there should be 5.5 gallons of wort.
- Ferment at 66ºF for two weeks. I highly recommend making a yeast starter and using yeast nutrients as well. Due to the low pH of the wort, it’s a harsh environment for the yeast, so having a large cell count and nutrients will help.
- After 2 weeks of fermentation, rack off into a secondary vessel and bottle or keg to a carbonation level of 2.2 Volumes.
- Allow to age for a minimum of 6 months before drinking.
A Primary Fermentation Sour Beer Recipe
- Yields 5 gallons at 5.4 % ABV.
- 8 lb 2-row malt
- 1 lb wheat malt
- 0.5 lb Munich malt
- 0.5 lb acidulated malt
- 0.5 oz aged (3 year old) Columbus hops (60 min)
- 0.5 oz aged (3 year old) Cascade hops (5 min)
- 1 tsp Irish moss (15 min)
- 1 pack of your favorite souring bacteria (e.g. Lactobacillus)
- 1 pack of your favorite ale yeast (e.g. Wyeast 1056)
- 1 pack of Brettanomyces yeast
- Mash the grains at 152°F for 60 minutes.
- Boil the wort for 60 minutes, adding hops and Irish moss according to the schedule above.
- Cool the wort to around 80-85°F and add the souring bacteria. Allow the beer to sour for 3-5 days.
- Once the desired level of sourness is achieved, pitch the ale yeast and allow the beer to ferment for 7-10 days.
- If using Brettanomyces yeast, pitch it after the primary fermentation is complete and allow the beer to ferment for an additional 2-4 weeks.
- Once fermentation is complete, transfer the beer to a secondary fermenter or keg and allow it to condition for 4 – 6 months.
- Bottle or keg the beer and carbonate it to your desired level.
- Enjoy your sour ale!
Note: This is a basic recipe, feel free to adjust the ingredients and ratios to suit your taste. Souring time, fermentation time, and carbonation level can also be adjusted to your taste.