How To Brew Lambic Beer: Belgium’s Spontaneous Wild Yeasts and Wonderful Beers

Lambic beer history is very elusive. Brewed in the Pajottenland region of Belgium southwest of Brussels and in Brussels as well since the 13th century.

Lambics are fermented by exposing the wort to wild yeast and bacteria that is native to the region in which it is brewed, as is the case in Belgium it is the Zenne valley.

This is unique to sour brewing as it is customary for some sour beers to be pitched with a “carefully cultivated strain.” This leaves the beer with its very specific flavor, dryness, vinous, and tart aftertaste.

Etymology of Lambic

Interesting note for those interested in words. The name lambic was first spelled as “allambique” in 1794. The initial ‘a’ was dropped and in 1811 it was called “lambicq.” Also, it was called ‘alambic‘ around 1829.

A less likely origin derived from the word “allambique” as it was derived from Lembeek, a municipality near Halle, Belgium. 

The Brewing Process of a Lambic

Lambic usually consist of a grist of typically 60-70% barley and 30-40% unmalted wheat. The wort is cooled overnight in a coolship, which is a shallow, flat metal pan, usually copper or stainless steel.

This wort is exposed to open air so some 120+ different types of microorganisms may inoculate the wort. The nighttime cooling process requires the temperature to be between 18°F (-8°C)  and 46°F (8°C).  

Although the cooling method of open air exposure is a critical component to this style, as is the wooden fermenting vessel. Over eighty microorganisms have been identified in lambic beer, with the most important being Saccaromyces cerevisiae, Saccaromyces pasroianus and Brettanomyces bruxellensis.

The air temperature during the months of October and May in Belgium is most ideal as most summer months are too warm and will result in spoiled beer. 

Style Profile for Lambic


Color of a Lambic ranges from pale yellow to deep golden. Age will darken the beer. Clarity is hazy to good.

Yonder versions are usually hazy, while older ones are clear. White colored head with poor retention.   


A sour aroma is often dominant in younger examples of this beer. As the beer ages, the sourness subsides and blends nicely with aromas of barnyard, earthy, hay, horse blanket.

A mild citrus like aroma is favorable. Older versions may also contain an apple or honey-like aroma. No hop aroma should be present. 


Noticeable lactic sour are present with younger versions of this beer. Aged versions tend to be more balanced and bring out the malt, whear, barnyard characteristics.

Fruity flavors tend to be noticable with younger versions and apple, rhubarb, or honey tend to be noticeable with aged versions. Sometimes citrus character is present, especially grapefruit.

The malt and wheat character is low with some bready-grainy notes. Hop bitterness if low to none. The sourness provides the balance in this case. Typically a dry finish. 


Light to medium-light body. Lambics dries with age. Medium to high tart, puckering quality without being astringent.

Traditionally, this beer is completely uncarbonated, but bottled versions can develop carbonation with age. 

Image Source: PintsandPanels

Tips for Brewing your own Lambic


The grist for a Lambic is usually 30-40% of unmalted wheat and the rest consists of Pilsner malt.


As for hops, the IBUs should be under 10. Since hops are antibacterial, they will impede the bacteria needed for this style.

Traditionally, these hops are old, not fresh, low alpha acid, and European. Stay away from high alpha acid hops and citrusy American hops. 


Traditionally, this beer is spontaneously fermented with naturally occurring yeast and bacteria found in oak barrels. The oak barrels are usually more neutral and therefore do not give off much oak character in the finished beer.

A mix of Saccaromyces, Pedicoccus, Brettanomyces, Lactobacillus are all common to use when trying to recreate the effects of obtaining wild yeast in Brussels and the surrounding countryside of the Senne River Valley.

Wyeast, White Labs, Imperial Yeast, and Bootleg Biology all have yeast mixtures that contain a mix of Saccharomyces yeast and the Pedicoccus, Brettanomyces and Lactobacillus. 

Lambic By the Numbers

  • Color Range: 3 – 7 SRM
  • Original Gravity: 1.040 – 1.054 OG
  • Final Gravity: 1.001 – 1.010 FG
  • IBU Range: 0 – 10
  • ABV Range: 5.0 – 6.5%

Martin Keen’s Lambic Recipe

Grain LME

  • 53%        4 lbs.       Bavarian Wheat Liquid Extract 
  • 40%        3 lbs.       Pilsner Liquid Extract
  •   7%        .5 lb.        Maltodextrin 


  • 1.00 oz         Aged Saaz – Boil – 30 min


  • 1.0 pkg   German Ale  Wyeast #1007
  • 1.0 pkg   Brettanomyces Lambucus Wyeast #5526


  1. Mash at 152°F (66°C) for 60 mins
  2. Boil for 60 mins 

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Frequently Asked Questions

What is Lambic Beer?

Lambic beer is a type of Belgian beer that is known for its unique fermentation process which involves spontaneous fermentation with wild yeasts and bacteria native to the Senne valley, near Brussels.

This results in a distinctively sour and often fruity flavor profile that sets Lambic beers apart from other beer varieties.

The brewing process is traditional and the recipe often includes aged hops which contribute a mild bitterness and act as preservatives, without overpowering the sourness of the beer.

How is Lambic Beer Made?

The process of making Lambic beer is distinctive and steeped in tradition. It begins with a mash of malted barley and unmalted wheat. After the mash, it’s traditionally boiled with aged hops.

The wort is then cooled in a large, shallow vessel called a coolship, allowing it to come into contact with the wild yeasts and bacteria in the air.

This spontaneous fermentation process can take several months to a year or more. The beer is often then blended with younger or older Lambics to create a more complex flavor profile, or it can be further fermented with fruits to create fruit Lambics.

What Does Lambic Beer Taste Like?

The taste of Lambic beer is notably sour, often with a dry, cider-like quality. The wild fermentation process introduces a complex array of flavors and aromas, which can include earthy, funky, or barnyard notes alongside the tartness.

The use of aged hops provides a mild bitterness which is balanced by the sourness. Fruit Lambics, where fruits are added for a secondary fermentation, have additional sweet and fruity notes overlaying the characteristic sourness of the Lambic beer.

How Long Does Lambic Beer Last?

Lambic beers are known for their longevity. Thanks to their high acidity and the presence of alcohol, they can be stored for many years, often improving with age.

While the exact shelf-life can vary, it’s not uncommon for Lambic beers to be aged for several years, with some enthusiasts aging them for decades. It’s advisable to store Lambic beers in a cool, dark place to maintain their quality over time.

What is the Alcohol Content of Lambic Beer?

The alcohol content of Lambic beer can vary, but typically ranges from 5% to 8% ABV (Alcohol By Volume).

The exact alcohol content can be influenced by several factors including the specific recipe used, the fermentation process, and whether the Lambic is blended with other beers or fermented with fruits.

The traditional brewing process and the long fermentation period contribute to the development of alcohol content in Lambic beers.

Transcript: Over the years I’ve built up quite the grain collection, but I’m not going to be using any of it in today’s beer. In fact, today’s beer is both going to be very fast to brew, but also test the very limits of my patience.

Let’s brew a lambic.

My name is Martin Keen taking the Homebrew Challenge to brew 99 beers in 99 weeks. And yes, still sporting a bit of a, a bit of a black eye.

Now every bit that I’ve brewed so far on my Homebrew challenge has had one thing in common. And that is that it has been an all-grain beer, but today I am brewing an extract.

Why? Well, when I started to look around at what other people are doing with their lambic recipes, it basically comes down to a pretty simple beer. It’s just some pilsner malt and some wheat malt.

And a lot of places were saying, well, you know what? You might as well just do this as an extract. And I have been itching to revisit extract brewing. That’s how I started.

There are different types of lambic. There’s fruit lambic, perhaps the best known style, at least here in the US there’s blended lambic, but I’m going to brew a regular old dry lambic.

Now this style of lambic is quite light bodied, it’s sour, it’s dry, and it’s pretty funky. And to get that level of funk while you need to condition this beer for about a year. Yeah, that’s right about a year.

Now in terms of recipe. Well, this is going to have a gravity of around 10 52. It’s going to be about a 5% beer as for the extract ingredients. Well, that needs just a little bit of explaining.

Now when putting this together, a lambic is typically 30 to 40% wheat and the rest is pilsner malt or barley. So I was thinking initially that I would just do 30% of wheat liquid malt extract and 70% of Pilsner malt extract, but that isn’t going to get me what I want.

And that’s because the wheat liquid extract, isn’t just wheat. So I looked this up and it turns out that 65% of the ingredients are actually malted wheat and the rest is malted barley.

So what I’m actually using my recipe is four pounds of Bavarian wheat, liquid malt extract, and three pounds of Pilsner liquid malt extract in my five gallon batch.

Here is my liquid malt extract. And while I’m heating up the water, I’ve got about six gallons of water here that I’m warming up.

Extract Brewing:

Let’s talk about what extract brewing is, and specifically the stuff that I don’t have to do today. So first of all, I didn’t add any water salts. Normally I would add some gypsum, calcium chloride and Epson salt.

I’m not doing any of that because I don’t have a mash. That is the second thing. There is no mash so there’s no grains here. I don’t have to worry about any of that. This is effectively all pre mashed for me now.

Extract brewing doesn’t mean you can’t use specialty grains. And in fact, most of my recipes that are available at Atlantic brew supply do have an extract version. And most of those do use some specialty grains in them as well. And you steep those.

So you stick them in warm water, uh, ahead of adding in the malt extract. Now, a lot of people do start out with extract brewing and eventually move on to all grain. But I don’t think that means in any way that extract brewing is like inherently bad or inferior to all grain brewing.

In fact, I did a video with some buddies where the three of us got together and we all brewed the same beer. We’re doing a Brewer’s best. What is it? Scottish ale. And one of us did it using an extract recipe and it turned out good for the extract version. We liked the most complexity of all three of the beers we brewed.

For 3% beer. That’s actually pretty good. Isn’t it? It tastes like to me.

Now I’ve got the water nice and hot, not quite as boiling, but the first thing I’m going to do before adding in this liquid of malt extract is turn off the heat because I don’t want any scorching when I add this liquid malt extract in, okay.

It smells just like yeast starters. This is a typical what I make my yeast starters from. Okay. Uh, now I’m just going to slowly add this in.

Think this stuff is the stickiest liquid known to man. Okay. I’ve got about three quarters of it in and I’m going to give this a stir. I think I’ve got that in there. Now I’m going to bring this to a boil.

And while this is heating up, this take a moment to about the hops. Cause I’m about to add those in, um, this beer should have no hot bitterness at all.

And in fact, you can get special types of hops “de bittered hops “that you can add in to a lambic to make sure that you get a little bit of hop character without any of the hop bitterness.

De-bittered Hops:

Um, I don’t have debittered hops, so I’ve gone about making my own in this, uh, this paper bag here. So to create your own debittered hops, you want to start with a low alpha acid. I’ve gone for Saaz hops and you want to treat your hops very badly.

Now, normally the way that I handle hops is I have buy a big bag. I use some in a brew and then I use my vacuum sealer to make sure that everything is sealed up tight, to get the oxygen out. And then I store the hops in the freezer and all of that helps keep the hops fresh. But what I’ve done now is deliberately oxidized my hops.

So a month ago I took a pound of Saaz hops. I put them in this paper bag and I’ve just left them out at room temperature for a month that should have done a good job of de bittering them.

Reached a vigorous boil now. So let’s add in these hops. Then we’re going to maintain the boil for 30 minutes, With five minutes to go. I do have one more ingredient to add in.

This is Maltodextrin, which is non fermentable sugar. So this is not going to be consumed by the yeast, but adding this, we’ll just add a little bit more body and an improved mouthfeel to the beer. I’m adding in half a pound.

I’ve got the wort cooled and added into for my fermentor. It’s now 68 Fahrenheit or 20 Celsius. Time to add the yeast. This is Wyeast 1007 German ale. Yeah.

So, so far so normal, I’m going to let this ferment for a week, then move on to the souring.

It has been fermenting for one week. It’s down to 1.019. It’s time to add the bugs. I am using this from the wild and sour series from wyeast. This is wyeast 5526, and it’s really going to give sort of a pie cherry sourness to this beer. And that’s it.

As I said, with the previous sour beer that I did, if you do have a glass fermentation vessel, that’s probably going to be better, but I’m using a better bottle, which is supposed to have low oxygen permeability.

And I am going to be aging this guy for a year. So I’m going to put this in my little basement room, along with my Flanders Red and let it do its thing.

The Tasting

Well, we, uh, we came prepared.

Yeah, it looks like we, uh, use the same closet today when we got dressed. Apparently. So today’s Lambic is not the beer that I brewed and is still maturing. Um, I’ve got some Limdamins. This is a fruit lambic. I wasn’t able to find a non fruit lambic, but it’s close enough. I think we’re willing to give it a try.

Uh, before we get to that, just a quick shout out to my nephew Jackson down in Australia, Jackson has his own YouTube channel whiplash productions. He has how to’s, animations, all sorts of cool stuff. Jackson is also the architect of my favorite photo bomb. Yeah, go ahead. And I’ll go check that out. Subscribe. Give him a couple of likes. Pretty awesome.

All right, so let’s get into this. Now. We do have a branded glass in here. Ooh, fancy. Can I have the branded glass? I’ll have the non branded one, right? Well, it’s a nice little box. Pretty. Right, now this came with multiple flavors. So there’s raspberry, uh, strawberry and peach. Peach.

What do you think? Um, I think we should start with peach. Don’t get much. These are teeny little bottles Aren’t they? So the bottle says this is a wild yeast fermentation. Exceptional complexity. All I smell is peach. Very peachy.

I think that’s what might be a bit too sweet. It’s very sweet. It’s very sweet. Not getting much sour at all. Not at all. There’s just like a little subtle sourness, but it tastes more peachy than sour. Yeah. Hi. Strawberry. I’m interested to see if it’s going to be the same color. Yeah. That one was like super mellow.

I assume this is going to be pinky gives assume, right? I think the raspberry one will be, Oh yeah. It’s different color. Oh, that was dark at the end. I feel like I should have swirled a little bit. Maybe is yours like kind of really cloudy. It’s cloudy. Okay. I’m going to give it a little swirl.

Smells like a subtle strawberry like a light strawberry smell. I think the peach was quite a strong smell, but this is a little subtler, that smells nice.

I think this time is a bit more solace in there like that. Yeah. I don’t like that. That’s got, um, for me there’s a taste of strawberry, but then there’s something else going on. I don’t, if I want to come back for a second sip. I don’t know why this one at all. No, it’s still the same.

Okay. One was good. One was definitely not good. Let’s see what we think of. Okay. Aw. That’s a dark dark looks that looks inviting. Promising. Yeah. Okay. Well it does look a nice raspberry color. Deep color. Yeah. That’s so to me that’s a real fresh raspberry tastes. Really good. Um, again, no sourness said the strawberry, I picked up the sourness. This one is, do you think it’s tart? Yeah. Yeah. Yeah. Okay. Yeah. I’m not getting any sort of Berry notes from it.

It just, Oh yeah. I meant to be saying about beer and what you think this is about, like I said, I think it feels like I’m just drinking a cider. Yeah. Yeah. It’s doesn’t taste, taste beery whatsoever. I could not tell you if it was like hop hoppy or weaty or bready or nuty. No, it’s none of those things. It’s, it’s raspberry and that’s it.

I wasn’t really surprised with two out of the three of them. I thought they were really good. I thought the one I disliked the most, I was going to like the most, but a bit shocked on that, but yeah, I enjoy trying these fruity lambics. Yeah, absolutely. And, uh, uh, Mark your calendar a year from now. We’ll uh, we’ll try my own as well. Okay.

But until then with your empty glass, cheers!

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