Floating dip tube optimisation

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LethalCorpse

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I'm seriously considering diving into keg fermentation, so I'm looking at floating dip tubes. I want to put these in my serving kegs too. I have a concern with how to use them without losing a lot of beer though.

All the ones I've seen suspend the end of the tube on a hook, an inch or two below the beer level. Great for extracting clear beer from the first pour, all the way down the keg. But what about at the bottom? The way I see it, the end of the tube is going to dive into the trüb long before the keg is empty. This will transfer all that yeast and debris you've been avoiding since the top of the keg. Or, if you stop transferring as soon as it hits the cake, you leave those couple of inches of beer above the tube.

This is much less of a problem for dispensing than fermenting, as there's a lot less trüb. It just means the last few pints are full of gunk instead of the first. But for a fermenting keg, this looks like a real problem.

The simple answer, of course, is "don't be greedy, RDWHAHB". But if you're fermenting in a keg you've already reduced your batch size quite a bit to allow head space. I don't want to end up with the serving kegs half full.

Has anyone encountered this, and have you come up with a solution? Are there floating dip tubes that hold the end closer to the beer level, or a way to get it to sit on top of the yeast cake when it gets to the bottom?
 

Sidney Harbour-Bridge

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You can buy pressure fermenters with floating dip tubes in various capacities, I have one that holds 35 L and one that holds 30, these are capable of fermenting and lagering 20+ L, you can also do closed transfers from them to your kegs if you want to reduce oxygen pick up
 

hotwaterpls

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I'd say it's probably less an issue than it may seem - if using a little mesh filter, there are 3 points you can attach to the dip tube float which will alter how high or low it sits under the liquid. Too high and you get foam, too low and maybe you get more yeast or trub at the end.

By the time you get to the end of the keg the contents have (presumably) been cold stored for anywhere from a couple of days to a couple of months, by which time everything is pretty well compacted. It's also not like the dip tube is swinging around like crazy in the keg, so it should just come to rest at the bottom as you get through the keg (which I don't imagine would kick up a huge amount of yeast or trub).

Ultimately no matter what, you have to sacrifice a little beer - plastic fermenters you lose a bit below the tap / on top of the cake, PET pressure fermenters you can angle but stir up the trub and still leaves maybe 200ml behind... it's limited, but you'll never get every last drop.

Alternatives include PET pressure fermenters which utilise a floating dip tube (and serve from or transfer to kegs), kegmenters of various sizes (which allow fermenting enough to fill a 19L corny or two, or more). If you're lucky, you can pick up 23 or 25L corny kegs and then still ferment to have 19L at the end and some headspace in the fermenter.

If you go the route of a regular 19L corny, some people cut an inch or so off the dip tube to leave behind most/all of the trub when transferring. Floating dip tube you can also cut to a length suitable to not pick up trub, or monitor during transfer.

I did a couple of batches in kegs before getting an all rounder and for the most part it went okay, but I did have transfer issues once or twice which were particularly frustrating (some people add a stainless nut or similar to weight the filter to ensure the line stays below the liquid level, which probably would have prevented the issue).

All this to say it's somewhat personal preference and a bit of trial and error to have the float as high as possible to not be sucking up trub and yeast but low enough to still get liquid out.
 

Lefty

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I've been using floating dip tubes for the last couple of years without issue providing you cut the tube to the correct length. They work well under pressure fermentation and serving from a tap/keezer set up. Can't say you lose any more beer when you get to the last couple of pours, no more than pouring your first couple of beers from a conventionally setup keg and dip tube. The yeast cake will harden over time spent at serving temp in the keezer. A filter attached to the floating tube is not going to catch much, as most I've seen are way larger than the 300 micron screen used during hopping. I would say give it a go and its probably only going to cost you about $10-$15 for the floating dip tube and a shortened liquid post.
 

thegoovna

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I pressure ferment in kegs and the biggest issue I found was the dip tube getting blocked when transferring double and even single dry hopped beers from fermenter keg to serving keg. I had initially cut the dip tube by an inch or so but still this was a problem, tried dry hopping in bags but the bag would get caught in the dip tube. I moved to a floating dip tube with the baskets and had no issues with blockages or with large volumes of beer being left behind. As far as the effectiveness of the filter, Lefty is probably right but just monitor the transfer and when it becomes cloudy you know when to stop. For all the pain of having blocked dip tubes losing a small amount of liquid, and it is only a small amount as suggested above, is an easy trade off for me. Non dry hopped beers are no issue with a regular cut dip tube.

You do have to reduce the batch size to ensure krausen doesn't come up through your spunding valve, I'd suggest an inch below the weld line works well. I do 30-34 litre batches in two corny kegs to overcome the reduced batch volume, which may be worth considering if your system and equipment allows. This gives me about 2 x 15-16 litres of beer each keg.
 
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