For most of beer's history, open fermenters carried out fermentation. Why did it change? Why should we consider using open fermentation again? It is considered the best method for producing Saison and many English styles. So, it's time to let your beer breathe! Welcome to the world of open fermentation, where we throw caution to the wind (but not our sanitation practices) and brew like our ancestors did. Buckle up and let's dive into this historic technique and how to do it right.
What's the Fuss About Open Fermentation?
Picture this: your fermenter, lid off, exposed to the world. Sounds risky, right? Well, it's not too bad, really. Before brewers knew about yeast, they would leave the fermenter open to the environment or stir it with the magic paddle. This would inoculate the wort with yeast. As the yeast propagates and ferments, a layer of carbon dioxide is formed over the wort. This continuous cushion of gas protects as new microorganisms in the environment cannot penetrate the gas layer to get to the wort. Thus, a relatively clean beer is produced.
Traditional fermenters are tall and relatively narrow, with an airlock or blow-off tube that applies internal liquid and gas pressure on the fermenter. These factors can suppress some of the flavour and aroma expression of the yeast. In contrast, open fermenters are often shallower and wider, and because they are not mostly closed like traditional fermenters, there is little to no liquid or gas pressure on the fermenter. This allows the yeast to express flavours and aroma more freely.
There are many breweries that have fine-tuned this technique, like Anchor Steam, Fullers, Russian River, New Glarus and many more that either solely or have some fermenters dedicated to techniques for specific styles.
The Saison Struggle: A Tale of Stubborn Yeast
Let's talk about Saisons. If you've ever tried brewing one, you might have encountered the infamous "Saison stall". You know the drill - your beer starts fermenting like it's running a marathon, then suddenly decides to take a nap at the 30km mark. Frustrating, isn't it?
The usual suspects for this fermentation are yeast strains like Wyeast 3724 Belgian Saison and WLP565 Belgian Saison I (AKA Saison Dupont strains). These temperamental little beasties are known for their "sprint and snooze" routine, often stalling out at a gravity of 1.030. Cue the collective groan of Saison brewers everywhere. This stall is because this strain cannot deal with modern semi-closed fermenters because historically when this strain was selected, it never had to deal with this environment. However, the solution and way to emulate this great beer is through open fermentation.
Open Fermentation: Your New Brewing Best Friend
Two main techniques exist for easy and safe open fermentation in home brewing.
Enter the unlikely hero of our story: aluminium foil. Yes, that shiny stuff you wrap your sandwiches in could be the key to Saison success. Using foil instead of an airlock creates an open fermentation environment that keeps our yeast happy and our beer flowing.
The other uses the lid and airlock, but only for the first 24 hours. Then, the lid is removed, and fermentation is allowed to take place. Once fermentation has slowed, the lid is reintroduced to protect the beer as fermentation slows and stops. This process takes more hands-on monitoring and action than the foil technique.
The Science Behind the Magic
Open fermentation also allows for better oxygen availability. Ideal gas laws don't exist, and the blanket of carbon dioxide is not a perfect barrier. A little oxygen does get through, but not enough to halt fermentation. This small amount of extra oxygen can lead to better attenuation, meaning your beer finishes drier and more flavourful.
How to Open Ferment Like a Pro
Ready to give it a go? Here's your step-by-step guide to open fermentation success:
- Grab some aluminium foil and your favourite sanitiser (Sani-Clean or Star San will do the trick).
- For carboys: Simply cap it with foil and give it a light crimp. Easy as!
- Using buckets? Place the foil over the gasket port and secure the corners.
- For the fancy folks with kegs and conicals: Remove the lid, cover the opening with foil, turned 90 degrees to hold it down.
Remember, we're going open, not reckless. Keep everything clean - we're not inviting every wild yeast in the neighbourhood to this party!
The Open Fermentation Revolution: Join the Movement!
So, are you ready to throw off the shackles of airlocks and try a traditional, authentic brewing technique? While this technique is commonly used on English and Sainson styles this technique can be used on almost any style. You might just find that a little rebellion in your brewing process leads to a lot of flavour in your glass.
Remember, in the world of brewing, sometimes the most unorthodox methods lead to the most extraordinary results. So take the lid off, and let your beer breathe the sweet air of freedom!
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