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How to Clean your Fermentor Without Scrubbing

Posted by homebrewdad on 1/28/2016 at 12:35:27 AM

No matter what you brew, no matter how often you brew, one constant remains - you have to clean your fermentor between batches. This can sometimes be easier said than done, as dried on krausen and fermentation byproducts can be difficult to remove - especially in vessels such as carboys, which have narrow openings that prevent easy scrubbing. And, of course, matters can be further complicated if you are using plastic fermentors that may not be compatible with scrubbing due to concerns about scratches.

Dirty Carboy

Luckily, there are ways around the problem that don't force you to rely on using a glass carboy and a carboy brush... nor do you have to resort to some high-tech microfiber cloth attachment for a power drill (though the tool nut in me does admit that these look pretty cool).

Method One: the Soak

To me, the best alternative to scrubbing is to simply not scrub at all. Fill your fermentor with a solution of hot tap water and PBW (OxiClean Free is a pretty good stand in, and costs a bit less). The manufacturer recommended strength for this application is one tablespoon of PBW per gallon of water; I have found that PBW is still quite effective at lower concentrations than this.

Allow the fermentor to soak for an hour or two; an occasional swirl seems to be helpful. I have let glass carboys sit overnight in this solution multiple times, though as I understand it, doing so may not be advisable (there is some evidence that extended soaks in strong cleaning solutions can cause damage to the surface of fermentors)... so I've stopped that practice.

Regardless, a good soak, followed by a thorough rinse, will take care of the vast majority of even the heaviest krausen deposits.

Method Two: the Rag
Unfortunately, there are occasions where even a strong soaking doesn't seem to take care of every bit of dried on gunk. If you're using glass, you may be tempted to break out the hateful carboy brush at this point... but what if you - like me - have long ago trashed your brush? Or what if you are using plastic?

The answer is to take a rag, wet it in some PBW/OxiClean solution, and insert it into your fermentor. You can then shake and rock the fermentor, which will cause a safe scrubbing action with the rag. Do note that for this method to be successful, you need to have very little free liquid inside of the fermentor, or else the rag will ineffectively float above the surface of the gunk. I have employed this method a few times, and have had great success with it.

Method Three: Ice, Ice Baby
Sea Salt

In four years of brewing, I had never run into a situation where some combination of the two methods above did not yield a sparkling clean carboy. However, earlier this month, I found myself employing a carboy that I may have let sit literally for months with dried on krausen inside. However, we didn't come here to gawk at my stupidity... so let's press on.


Anyway, the long soak took care of the lion's share of the grime, but there were a couple of spots left. To my dismay, I discovered that the rag method was only marginally more effective than the soak alone; even after multiple attempts, a few noticeable spots of residue remained. I considered the hateful carboy brush, but refer above to my brilliance (i.e. I got rid of the thing some time ago). So what could I do?

Googling took me to several homebrewing forums, and eventually, to a funky home remedy - ice and salt. Desperate, I gave it a try.

I poured probably a tablespoon or two of sea salt - chosen for its larger, more abrasive, form as opposed to the normal table salt that I also owned - into the carboy, then added a couple of handfuls of ice cubes from my ice maker. I then shook these around... and lo and behold, it worked like magic.

Yes, the salt did cause the ice to melt rather quickly; I had to dump out the resulting water and add more ice once. However, this method cut the otherwise impenetrable crud in little time, leaving me with a sparkling clean surface. In the future, I may just skip ahead to the ice/salt method if a soak doesn't do it, as fishing a rag out of a carboy opening can be a tad annoying.

Method Four: Rice, Rice, Baby
Yes, I went there. Chalk it up to dad humor.

In my case, my carboy was already 100% clean, but I decided to do a little more homework for this post. That process led me to another pretty ingenious method that is supposedly extremely effective.

Take a quarter cup of rice, a couple of tablespoons of baking soda, and just enough water to allow the above to slosh around. Dump these into your fermentor, and shake well. From what I have read (again, I have yet to try this one, myself), there is no crud too stubborn to stand up to this technique; the rice supplies the grit, and the baking soda supplies the magic. I'll have to give this method a try, just to see for myself how well it works.

So, there you have it - a few easy ways to clean a fermentor that don't rely on funky attachments or a scrub brush. Do you have some other tried and true methods? Please share them in the comment section below!

Tags for this post: clean, carboy, fermentor, soaking

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I utilize method 1. I quickly learned I could save $ by using less pbw. What I do is fill the better bottle up to about 2 gallons and add my PBW. Then I get some tin foil and a rubber band and tightly secure it to the top. I then flip the better bottle end-over-end and leave it like that in a bucket (to catch any slow drip). A virgorous shake once or twice over 30 mins and everything is gone. I have had issues with residual crud if I just let it sit for multiple hours

posted by Brettwasbtd on 1/28/2016 at 08:28:28 AM

I have a marks keg washer and love it. I'll make 4 litres of pbw solution and let the carboy sit on it for 20 minutes or so (while I do other things). Sometimes for the caked on stuff I'll take a brush to it then another 20 minutes or so.

posted by sniffton on 1/28/2016 at 11:12:43 PM