What exactly does the term sour beer mean? I guess, in a way it means beers that are influenced by more than just brewers’ yeast. This subject really dates back to 1876. Prior to 1876 brewers did not even know that yeast existed, let alone what it did. You can just read the original German Reinheitsgebot – it only included water, malt & hops.
In 1876, Louis Pasteur examined foul smelling beer under his microscope. Besides yeast cells, he was able to identify other bacteria as well. In order to keep other microorganisms at bay certain methods were applied, shorter shelf lives, higher hop rates (hops act as a natural preservative in beer), higher alcohol volumes and other arcane methods.
It should be noted that at one point in history, all beers would eventually become sour. Only now that modern technology (refrigeration & modern cleaning systems) are readily available are we able to go back and purposefully brew a sour beer. Like many things in life, such as bell bottoms, things in life are circular. So while three generations ago they were trying to get rid of sourness in beer, we are now trying to bring it back in.
Beer vs. Wine
Yeast
The history of both wine & beer making are quite ancient. The earliest evidence of wine making dates back to 7000 BCE & beer making dates back to 5000 BCE. The brewing process of beer has become much more modernized over time compared to that of wine. Most fine wines, like in the old days, use the wild yeast on the grape skins to aid in the fermentation. Brewing on the other hand has moved over into a direction of total control. Highly specialized yeasts & standardized cleaning processes have tried to eliminate variation from different batches.
When you look at the high end world of wines, vineyards always have different vintages that turn out better than others. However, with beer people have become used to every batch tasting the same. Maybe this is why more interest is developing in the world of sour beers. More variety & randomness – a little bit more excitement!
A major flavor change agent is yeast and what it can do over a long period of time. The first beer we are going to talk about today is quite a modern example because in this case there is only brewing yeast at work.
In the glass the liquid is a dark amber colored beer with good clarity. The aroma is alive with warm flowers, apricot, banana and bitter almonds. The flavor follows in a similar fashion with notes of apricot, almond cake, citrus fruits, and rich malt. Super Baladin Reserva finishes quite dry and tangy.
Bacteria
Moving on from just yeast we head into the world of bacteria.
Berliner weisse is a cloudy, sour wheat beer that is light in alcohol, about 3 – 4% ABV usually. This was a very regional style around Berlin that dates back to the 1500s. In the 19th century it was the most popular style of beer in Berlin and there were 700 breweries brewing it. There are a few theories on how the style came about: 1) That it actually originated in Hamburg but ended up being brewed in Berlin, and 2) That migrating Huguenots developed the beer style on their way from Flanders to Northern Germany.
The more popular wheat beer is the Bavarian hefeweizen, this is different though. The only thing they have in common is that they both use wheat. Modern brewing uses a lower proportion of wheat, generally ranging from 40% to 60%, and deliberately create sourness by a secondary fermentation in the bottle or by adding lactobacillus. Lactic acid producing bacteria can produce a lot of acid if pitched at a high enough cell count (there are two common types lactobacillus & pediococcus). During primary fermentation the brewers yeast will tend to dominate these bacteria but once all the simple sugars have been eaten the bacteria will make their presence known.
Authentic old recipes of Berliner Weisse suggested adding the hops during the mash and not the boil. This was done because unlike barley, wheat does not have a husk so it can clog up during the lautering process (it also has a lot of sticky gluten), so the leaves from the hops actually helped this process.
Bayrischer Bahnhof Berliner Weisse
It appears a straw color with some haze, big dense head and insistent sparkle when poured correctly. The nose is sweet and sour notes with a hint of lemons and raspberries. The flavors are mellow with raspberry and citrus flavors with a sharp lactic tartness in the background. This beer also finishes dry, crisp, and tart.
Moving on to the next souring agent leads us on a little history tour. As touched on in my previous article Belgium has its own Mason/Dixon line in a sense. This split in the Belgian culture led to different brewing styles between the Northern & Southern parts. The Dutch brought an influx of new spices whereas the French were known for their use of spices & fruits in beer.
These influences and split personalities led to lots of experimentation including using herbs, spices and hops, other stranger substances such as mustard, coffee and chocolate along with wild fermentation & crazy yeast strains.
Often when people talk about sour beer most people think about lambics, however lambics are actually a minority in the world of sour beer. A few of the qualifications for lambics are: 1) They must be brewed around Brussels, Pajotenland region, 2) They use a special brewing process called the turbid mash technique, and 3) They rest in a coolship overnight and 4) They are racked to the horny tank after the coolship rest (Horny because it is ready to go, aka ferment).
There are many more sour beer styles other than lambics. Framboise for example, is a style brewed with raspberries. It is usually assumed that the base beer for a framboise is a lambic but this is not necessarily the case. Brewing with raspberries can be tough for a couple of reasons: 1) They are quite expensive 2) They have a lot of water weight 3) They completely decompose during secondary fermentation which can lead to filtration problems and 4) They will increase the perception of dryness and add quite a bit of acidity and possibly some astringency.
Birra del Borgo’s Rubus con Lamboni is a sour ale made with a raspberry infusion. Raspberries were used for 15% in weight and are special from the Sudtirol Alps in northern part of Italy. Rubus is also a beer that spends time in oak barrels.Rubus uses pilsner, wheat & caramel malts along with Hallertauer, Northern Brewer & Saaz hops.
Barrel Aging & Blending
After all this talk of fruits & bacteria we finally arrive at barrel aging & blending. Why are the barrels usually made out of oak you might ask? Oak is quite strong, resistant to decay and generally easy to take care of. With a barrel, the previous use, size & method of production will all have an effect on the future liquid. Barrel aging beer is actually not a modern invention even though it currently seems to be en vogue.
Prior to our modern brewing time they didn’t have welded stainless steel tanks, back then even the brew kettle was made from wood! Wood can provide up to 200 different flavor compounds to a beer/wine/spirit. Only about a dozen can actually be tasted by the human palate. Of those we’ll only really talk about 3 as they are the major ones: 1) Vanillin – vanilla like, sweetness 2) Tannins – dry, astringent & acidic characteristics and 3) Methyloctalactones – a spicy character that depends on the wood.
For a little background most wine barrels tend to be made of French oak, bourbon barrels for example are made of American white oak. Traditionally it was thought that American white oak was inferior, however the problem was actually with the production method. The French dry their wood for 24 months whereas American oak was kilned to dry it out quickly.
Brettanomyces is a type of wild yeast. It actually ferments better with the presence of oxygen and it will ferment for about 18 months. Brettanomyces can break down more complex sugars than brewing yeast. That is why most sour/wild beers are much drier in character. Some common characteristics brett brings in are “horse blanket & barnyard funk.” Brett is also an oxidative yeast so if there is too much oxygen you will end up with actetic acid which creates vinegary sourness. Temperatures above 75 F will also create problems and too much acidity.
The color is a red amber, caramel brown, with some golden glints. The aroma has hints of spices, fruity, almost gingery. The flavors coming from the Rum aging give a lot of complexity (tobacco, ginger, spices and woody). On the palate it is sweet and crispy, explosion of freshness, woody and hoppy, as well as a medium hard bitter attack going on a very long aftertaste with a spike of fresh fruits remaining.
Fruits/Barrel Aging & Blending
Putting everything together we get Del Ducato’s La Luna Rossa which uses barrel aging, fruits & blending to arrive at an extremely complex product, and a wonderful way to wrap up…
Birrificio Del Ducato La Luna Rossa
The start is a sour base which has undergone at least 2 years of mixed fermentation with acetic and lactic bacteria as well as Brettanomyces strains. Amarena and morel cherries are then added for additional flavor for at least 6 months. The beer is then blended with part L’Ultima Luna and part young beer and poured into numbered bottles indicating the year of the cuvee. 12 more months of maturation in bottle are required before entering the market.
La Luna Rossa is an intense amber with ruby highlights.The nose is extraordinarily complex with fruity aromas of morel and amarena cherry perfectly blending with subtle ethereal notes, acetic and lactic flavors and hints of oxidized malts.It has a sapid, full mouthed lasting palate with a magnificently elevating sour finish.