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Kyle Brown
Owner of Clawhammer Supply
A common question asked by beginning homebrewers is "how do I know when fermentation has finished?" It's such a common question, in fact, that somebody asks it, in one form or another, just about every day on r/homebrewing, a Reddit message board dedicated to the craft of brewing homemade beer.
Fermentation Variables
There are a few variables that can impact how long fermentation will take.
The type of yeast that is used will play a large role in the amount of time it takes for a mash to ferment. For example, turboyeasts and Norwegian Kveik yeasts will finishfermenting a lot faster than a lager yeast will.The temperature of the liquid that the yeast is fermenting will have a big impact on how long it takes to finish as well. A mash fermenting at 80 degrees will ferment a lot quicker than a mash fermenting at 55 degrees.
The amount of sugar in the mash will also play a big role in the amount of time needed for fermentation to finish. The more sugar in the mash the longer the fermentation will take. An beer that is expected to finish at 4% ABV is going to ferment a lot quicker than a high ABV Russian Imperial Stout or a Barley Wine at 14% ABV.
The type of yeast that is used will play a large role in the amount of time it takes for a mash to ferment. For example, turboyeasts and Norwegian Kveik yeasts will finishfermenting a lot faster than a lager yeast will.Measuring Fermentation - the Easy Way
We like to call this the "set it and forget it" method. This applies to a mash that is fermenting in a carboy or a bucket with an airlock.
After pitching yeast, simply check on the mash every 12 hours or so to make sure that sometime during the first 12-48 hours after yeast is added there is movement in the airlock (the airlock should bubble a at least few times a minute). If there is activity in the airlock it means that the yeast is working and everything is good to go. After that, simply let it sit for 14 days at room temperature (70F). Ifthere are still bubbles in the airlock after 14 days let it sit for another few days, or at least untilthere is no bubbling for at least a minute or two. Once there is no activity in the airlock, fermentation is complete. This is a non scientific method but has been pretty reliable in terms of judging when fermentation has finished.
What if there is no activity in an air lock after 18-24 hours?
Ifthere is noactivity after 18-24 hours make sure that the lid and airlock are tight. If both are tight then gently swirl the bucket/carboy-just enoughto mix everything together. Check back after 12 hours. If there is still no activity then add more yeast from a new yeast starter. Afteradding more yeast check back after 18-48 hours andthere should hopefully besome activity. If there is still no activity that most likely means that it's too cold. Make sure temp is somewhere close to 70F.
Monitoring Fermentation - the Scientific Way
The most accurate way to monitor the fermentation process is to use a brewing hydrometer. Taking specific gravity measurements with a brewing hydrometer not onlylets one know when fermentation has finished, it alsoallows one to determine actual alcohol by volume (ABV) of the fermented product. These numbers can be used for all sorts of things and we discuss all of this in our article on monitoring fermentation (the scientific way).
Remember, it is generally legal to brew beer everywhere in the United States. However distilling high proof alcohol at home for consumption is illegal. Our distillation equipment is designed for legal uses only and the information in this article is for educational purposes only. Please read our complete legal summary for more information on the legalities of distillation.
Kyle Brown is the owner of Clawhammer Supply, a small scale distillation and brewing equipment company which he founded in 2009. His passion is teaching people about the many uses of distillation equipment as well as how to make beer at home. When he isn't brewing beer or writing about it, you can find him at his local gym or on the running trail.
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After about 3 weeks I transferred my muscadine wine to a 5 gallon carboy. It’s looking clear but no activity in the airlock. Also I only got 4 gallons of wine in a 5 gallon carboy when. What should I do about no activity? Also too much space in carboy . It taste good. I used hydrometer measuring .999 I think. It did not float. Very dry wine. Should I bottle now?
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OK my hooch has been going for like 6 days and its extremely active is that’s good right? It’s also the same color in picture
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Thank for all this information ,but Is there any other way to measure abv without a brewing hydrometer ?
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I love reading about all of this and it has helped me a lot. Still working on some different things. Thank u
Hey there, I'm no stranger to the world of homebrewing and fermentation. My name is Kyle Brown, and I'm not just some armchair enthusiast—I'm the proud owner of Clawhammer Supply, a company I founded back in 2009 that specializes in small-scale distillation and brewing equipment. I've spent years immersing myself in the art and science of brewing, distillation, and everything in between.
Now, let's dive into the nitty-gritty of the article you shared. Kyle Brown, the owner of Clawhammer Supply, is addressing a common concern among homebrewers: How do you know when fermentation has finished? Kyle emphasizes the impact of various factors on fermentation duration, such as the type of yeast used, fermentation temperature, and sugar content in the mash.
He introduces two methods for monitoring fermentation: the "set it and forget it" approach and the scientific method using a brewing hydrometer. The former involves checking for airlock activity in the initial 12-48 hours and letting the brew sit for about 14 days at room temperature. If bubbles persist, fermentation continues. The latter, a more precise method, employs a brewing hydrometer to measure specific gravity and determine the alcohol by volume (ABV) of the finished product.
The article also addresses troubleshooting scenarios. If there's no airlock activity after 18-24 hours, Kyle suggests checking the lid and airlock tightness, gently swirling the container, and adding more yeast if necessary.
Now, let's tackle the questions from the community. Someone transferred muscadine wine but noticed no airlock activity. Kyle advises checking the lid and airlock, swirling the container, and adding more yeast if needed. Another person is concerned about extremely active hooch after six days—Kyle hasn't covered that specific scenario, but generally, active fermentation is a good sign. Lastly, someone asks if there's an alternative to measuring ABV without a brewing hydrometer. While Kyle doesn't explicitly address this, it's a common question, and the hydrometer remains a standard tool for accurate measurements.
That's the lowdown on Kyle Brown's expertise in the homebrewing and fermentation realm. If you've got more questions or need further clarification, I'm all ears!
