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Product Review:
Item: Wensel's Counterpressure Filler
Rating: B+
In sum: A well-conceived and executed filler, better-designed than most homebrew fillers; not up to the standard set by the famous Melvico filler, but with its good performance & half the cost, it's a winner!
The Wensel Counterpressure Filler is a device used to fill bottles of carbonated beer (or other beverages) from a keg, without losing its carbonation. It is sold by Mr. Wensel (the manufacturer) through his book publishing web site in Florida (www.backyardpublisher.com) and it sells for $250 plus shipping.
First, the "what, why and how" of counterpressure filling.
WHAT: Counterpressure filling means simply, filling a bottle that is pressurized with carbon dioxide (CO2), with carbonated beer. It is the alternative to priming beer with sugar and carbonating naturally.
WHY: The purpose of counterpressure filling is to get carbonated beer into bottles from a keg, without a) oxidizing the beer, or b) losing the beer's carbonation. Filling under carbon dioxide pressure eliminates the chance of the beer mixing with oxygen (because the bottle is purged of air) and getting an oxidized "homebrew" off-flavor that can occur when we bottle with a typical spring-loaded bottling cane. You know, when the bottle first starts filling, it sprays the beer into the bottle and mixes it with oxygen...i.e. oxidizing it. And in a counterpressure system, the CO2 that's dissolved in the beer stays in the beer rather than coming out of solution as foam, because the bottle remains pressurized with CO2 during the whole filling process.
But if we already keg our beers, then why would we want to bottle it? Well, we might want to send beers to competitions which require bottled beers. We might want to empty a keg to make room for a fresh beer. Or, we might want to take some bottles to a party. Lastly, counterpressure filled bottles don't have any yeast sediment in them which comes from priming and natural carbonation.
HOW: Counterpressure fillers work through a series of valves by sealing the bottle, purging air from the bottle with CO2 pressure, and opening a valve to allow the already-carbonated beer to flow from a keg that is also driven by CO2 pressure. Because the beer keg and the bottle are initially under the same amount of CO2 pressure, this "equilibrium" or equalized pressures in both bottle and keg will prevent beer from flowing into the bottle, unless we first bleed off some of the pressure from the bottle by way of a valve. As we bleed pressure from the bottle, the higher pressure still on the keg will then push beer into the bottle. Thus, by controlling the rate of pressure bleeding from the bottles, we control the rate of beer going into the bottle.
Is it a lot of work and bother? Depends on your filler and kegging setup, how much beer you need to bottle during a given session, and your definition of "bother". Yes, if all you're doing is filling 3-4 bottles to send off to a competition, it's kind of a pain to set it up, sanitize it, and clean it afterwards. But if you are bottling an entire batch of MSPA, or emptying the last gallon from a keg to make way for a new beer, it is definitely worth whatever time and effort are involved. Many people also think that for every day, routine homebrew bottling use, it's the way to go rather than priming and carbonating naturally, because YOU control the carbonation level in your beer, and you have no sediment. Once it's set up, the filling & capping operation only takes a minute or less per bottle.
Comparing the work and processes involved with the two methods of carbonating and bottling (natural vs. counterpressure), starting with a secondary fermenter of beer that is ready to be bottled:
Natural Carbonation:
Sanitize bottling bucket, racking cane, bottling cane and hose;
Transfer beer from secondary to bottling bucket;
Boil water to dissolve priming sugar; add to beer;
Sanitize bottles and caps;
Fill and cap each bottle;
Clean secondary, bottling bucket, hoses and canes;
Wait 1-2 weeks for carbonation to occur.
Advantages:
inexpensive - you already have the equipment to bottle this way;
arguably slightly less work involved;
ummm......some people like that yeast sediment in their beers?
Disadvantages
produces sediment in bottle;
takes longer before beer is ready to consume;
risk of oxidizing beer due to aeration of the beer when bottles are filled;
risk of exploding bottles due to premature bottling, over-priming, etc.
at the other extreme, occasionally bottles do not carbonate at all, due to weak yeast, cool temperatures, the moon & stars being in the wrong place, etc.;
Counterpressure Carbonation:
Sanitize keg, racking cane and hose;
Transfer beer from secondary to keg;
Wait 1-2 weeks for carbonation;
Sanitize bottles, caps, and counterpressure filler;
Fill and cap each bottle;
Clean secondary, and counterpressure filler before putting it away.
Advantages
Sediment-free homebrew in bottles;
You determine the exact carbonation level you like with no guessing...it always works;
Gives you the ultimate in flexibility to keep your beer on draft, but fill only a few bottles as needed for competitions, taking to parties/giving as gifts, or emptying a keg if you need to make way for a new batch;
No risk of oxidizing your beer while bottling (i.e. that stale "homebrew" aftertaste);
No risk of exploding bottles due to premature bottling, over-priming, etc.;
You are out of things to put on your Christmas or Birthday wish list for your Spousal Unit to buy for you...you need this more to help your Spousal Unit than for yourself.
Disadvantages
Expensive. In addition to the expense of the filler itself and all connections ($80 - $250), it requires the expense of at least a basic kegging setup, including a 'fridge where you can keep the keg cold;
arguably more work involved than simple priming and bottling, especially if you fill only a small number of bottles.
inconvenience: this operation is best done wherever you keep your kegs and CO2 tank so you don't have to dismantle everything, whereas priming and bottling the old way can be done easily in the kitchen. I set up my CP Filler operation directly on top of our washing machine, which is right next to my beer 'fridge. Good, convenient work surface, and spills run right down into the washer.
For further reading on the subject of counterpressure bottling, I refer you to an excellent article in the Fall 1995 Issue of Zymurgy magazine. Different models of CP fillers are tested and presented for comparison...unfortunately, the Wensel CP filler was not manufactured at the time (I don't think), so it is not included.
The Wensel at work
For
those club members who attended Bottling Day for our Clay Pipe Project, you will
recall seeing, and perhaps even operating, the Wensel filler (at left is Greg
Lambrecht filling a bottle of Midnight Special Pale Ale with it). Clay
Pipe's Gregg Norris acquired it to double our bottling capacity, since a little
math suggested that we would have been there for two solid days without a second
filler. While searching the internet for counterpressure bottle fillers,
this unit was the only one I could find that wasn't one of the various homebrew
CP fillers that require the user to hold it onto the top of the bottle and
applying force to keep it under pressure, while fiddling with one or more valves
to purge, pressurize, and regulate the beer flow. Gregg spoke with Mr.
Wensel, who knew what he was talking about and has his own machine shop where
he makes each CP filler that he sells.
I don't know the filler's exact configuration as delivered, because by the time we operated it, Gregg had made a few fitting modifications to fit with the brewery's connections. He also added a needle valve and a separate purge valve to the filler's gas relief port for greater flexibility, and more effective CO2 purging. See the inset below for pix and more information.
 This
top view (right) shows the "T" fitting which
was added by Gregg to replace the original single needle valve for
bleeding gas pressure. The center of the "T" goes to a new bleed
valve which allows precise control of the rate at which gas is bled
from the bottle, which in turn regulates the rate of beer flowing into the
bottle. This valve's new configuration also allows for very easy
"blow-off" of any foam in the bottle as it fills, as the tube
coming out the other end of the valve can be directed to a cup or a bucket
to catch any "blow-off" foam.
The other line off the right of the "T" goes to the blue & white plastic on/off purge valve which Gregg installed to the upright post of the filler. The photo at left shows this on/off valve's connection, which very conveniently allows the operator to instantly pressurize with CO2 and then release pressure from the bottle to purge air from the bottle prior to filling. |
Also as delivered, the Wensel filler
doesn't come with a fill tube, to purge and fill from the bottom of the bottles.
With most CP fillers, both the gas and beer fill the bottle from the bottom
through the same tube, on the theory that as the bottle fills with CO2
from the bottom, air is more completely forced out through the relief valve at
the top of the bottle. As for beer, I guess the theory is that filling
from the bottom causes less turbulence and less foaming.
The Wensel CP Filler fills both gas and beer from the top. There is just a short stem where the beer comes into the bottle. This might trouble some people, who prefer the logic and comfort of filling from the bottom (i.e. less turbulence). And since CO2 enters the bottle from a separate vent around the top of the fill tube, there is no way to reconfigure this to fill with gas from the bottom, even with a fill tube. CO2 is heavier than air, and the Wensel web site discusses this and advises that adequate displacement of air occurs by filling from the top. Gregg Norris of Clay Pipe Brewing Co. seemed to think that it was probably OK, but out of caution he added the purge valve as shown and discussed in the box above, to be able to quickly pressurize and release the CO2 several times to thoroughly flush the bottle with CO2. The manufacturer discounts the need for a fill tube, and after my experience with it at home I tend to agree with him. Further down in this article, I discuss my personal observations and results with using the filler at home without the fill tube. But you can add a fill tube if you wish so that it will fill beer from the bottom of the bottle. Gregg added one at the brewery. It came loose, so he cinched it on with a very small cable tie.
The Wensel at home
Before he bought it, Gregg had mentioned
the possibility of selling the Wensel CP filler to the club or an interested
club member when we were done with the Midnight Special project, as he doesn't
really do much bottling at the brewery and he already has a Melvico
filler. With that in mind, I am borrowing the Wensel filler with the
likely intention of making it mine.
Overall, the Wensel CP filler seems to be
well conceived and put together. It is compact, and made of sturdy and
lightweight aluminum, so both storing it and carting it around are very
easy. The operation of the locking lever is smooth and reliable, though it
seemed to have some "play" in it until I tightened up a few of the
lock nuts a little bit. The
filler is infinitely adjustable for any size bottle, by turning the red thumb-screw
on the back of the filler head and simply sliding it up or down the post, and
tightening it back up. 
The primary control lever is the small blue-handled guy on the left of the filler. It pivots back and forth, and has three positions:
- off (rear)
- gas only (middle, or upright)
- liquid (front, as shown in this side-view photo).
Before filling bottles with the Wensel or any other CP filler, there are a few things you should do. The first, is to turn down the temperature in your beer fridge a day or so before you plan to bottle, to get the keg as cold as possible. Second, make sure your beer is carbonated to the level you prefer before bottling...and consider jacking up the pressure by a few pounds a couple of days in advance of bottling. Even with the most efficient filler, tests show (see Zymurgy Magazine article referenced above) that your beer will lose 5-15% of its carbonation. For most purposes, that's probably not even noticeable. But if you want to be anal about it, or if you typically dispense your kegs at a pretty low setting (5-6 lbs.), I would boost the pressure to 10-12 lbs. about 5 days before bottling.
While not intending to replace the manufacturer's instructions (which I don't have anyway), this is the routine to operate the Wensel CP filler. By the way, I didn't mention this before, but there is another feature of the Wensel that distinguishes it from other hand-held homebrew CP fillers. Most other fillers require you to have two separate connections to your CO2 lines, one to the filler for pressurizing bottles, and the other to your keg to push the beer. Such fillers require either a manifold off your CO2 tank, or inserting (i.e. cutting) a "T" connection somewhere in your CO2 line to supply gas to the filler. The Wensel avoids this by providing a CO2 Out port on the filler head, which connects to your keg to push the beer. Anyway, here goes...
- Make sure the blue control lever is set to the OFF (rear) position;
- Connect your CO2 supply line to the "CO2 In" port on the Wensel;
- Connect the Wensel's "CO2 Out" port to your keg's Gas In connector;
- Connect the Wensel's Liquid port to your keg's Out (beer) connector;
- Make sure your CO2 gas line is turned on, and set your CO2 tank regulator to somewhere around 20-30 lbs. pressure;
- Place an empty bottle on the base of the filler, and adjust the filler head so that it locks securely onto the bottle when the locking lever is raised up, and lock it onto the filler;
- Start the gas flow to the bottle by raising the blue main control lever to the upright (middle) position. You can monitor the pressure in the bottle by viewing the pressure gauge.
- In our modified configuration, we now can purge air by turning the blue purge valve to ON which releases the pressure from the bottle, then shutting it off to refill, and repeating this process a few times. Again, you can monitor the pressure in the bottle by watching the gauge. In its original configuration, I believe you control the pressure in the bottle by turning the bleed valve.
- After a few moments (or several purges of air in the modified configuration), flip the control lever to the LIQUID (front) position to begin beer flowing into the bottle. Adjusting the bleed valve will control the rate that beer fills the bottle...opening the valve allows a faster flow, closing the valve slows the flow.
- When the bottle is filled to the desired level, set the control lever to the OFF (rear) position.
- Lower the yellow locking lever to release the bottle.
- Immediately put the bottle under your capper. If necessary before applying the crown cap, tap the bottle sharply with a metal tool (wrench, pliers, etc.) to cause a brief foam-up of CO2 gas. This will purge the headspace in the bottle of any air. Apply your cap.
- Next bottle...
The fill rate depends on factors such as the CO2 pressure setting, the carbonation level of your beer (more carbonation = more foam = slower fill settings), and how well you regulate the purge valve to control the rate of beer flow. At the brewery, the filler filled a 22-oz. bottle in about 50 seconds. Here at home, it was about the same, and a 12-oz. bottle fills in about 25-30 seconds. I tended to keep more pressure on the bottles than was probably necessary, so if you really tried you probably could obtain faster fill rates.
The only thing about the Wensel filler
that warrants a genuine complaint is the lack of stability when it stands on its
base. The base is a small, flat piece of
aluminum that is just about large enough for the filler to stand up straight on
its own without tipping over, assuming the surface if level and flat. If
you look at it crooked, or if you bump the table it's sitting on, it could tip
over. The machine just needs a wider and maybe a heavier base, or maybe a
3-point footed base like the Melvico. At the brewery, it was clamped to a table,
which worked fine and makes for a pretty easy one-hand operation. I have
since rigged it to a plastic cutting board, with steel mirror clips holding it
down on all four sides, for more stability. The clips are ¼" steel
mirror clips I found at Home Depot, and they work perfectly to hold the filler
firmly upright for easy one-handed operation.
Now, about the lack of a fill tube.
When I tried the filler on a test keg (before bottling my competition beer), I 
tried it without the fill tube first. As the manufacturer's web
site says (and after using it this way, I think I agree with him), you really
don't need a fill tube. Once the bottle is purged and pressurized, there
is no air in the bottle which would oxidize the beer, and the CO2
pressure in the bottle will keep the CO2 in the beer. I had
very little difficulty with foaming beer. This picture is a 22-oz. bottle about
half full during my inaugural filling operation. You can clearly see
the beer level in the bottle, and there is only a negligible amount of foam on
the surface.
Here are some other foam-related observations:
- If your bottles are cold, you can minimize any foaming issues with more highly carbonated beers. So if possible, keep your sanitized empty bottles in your beer 'fridge until just before you need them. When cold carbonated beer hits a warm bottle, the beer will warm up causing the CO2 to spontaneously come out of solution = foam.
- Bottles tended to get slightly more foamy if the pressure relief valve was opened up to allow the beer to flow faster, particularly at the beginning of a fill. If I slowed it down at first, then opened it up a bit as the bottle filled, I had fewer foaming issues.
- It also tended to be slightly more foamy on 22-oz. bottles than on 12-oz. bottles. I guess that's because the beer had a longer drop to the bottom of the larger bottles which might have caused it to foam a little. But even then, keeping sufficient CO2 pressure in the bottle kept any foaming down to a negligible amount (see bottle photo above).
- I bottled about 15 bottles (a mix of 12 and 22-oz. bottles) with it during my first home use, and maybe had three bottles that had a significant foam issue, including the very first test bottle.
- I used the Wensel CP filler with two different beers, one of which was significantly more carbonated than the other. The more highly carbonated beer was more susceptible to foaming, especially if I allowed the bottle pressure to drop too quickly (i.e. if the bleed valve was opened too much). Keep the pressure on the bottle and slow down the beer flow rate if necessary, and any foaming issues should go away. You're not going anywhere, so just slow it down.
- If a bottle was a little too foamy when I was about to release it (such as when I allowed a bottle to fill too quickly), I just let the foam escape (i.e. blow-off) through the bleed valve, and fill to the normal level. I also found that shutting off the beer flow but keeping the CO2 pressure on the bottle for a moment or two kind of slowed down any major foaming...or at least bought me some time to prepare to get that bottle to the capper more quickly.
A particular advantage of not using a fill tube is that you can determine the fill level exactly. With a fill tube, you have to over-fill to compensate for the space the tube itself takes up inside the bottle. With the Wensel filler, you stop the beer flow exactly at the fill level you want.
Before use, I ran a couple of bottles worth of Star San sanitizing solution through it, let it sit for a couple minutes, flushed it out with beer until the sanitizer was gone, and then started filling. Cleaning it afterwards involved running a few bottles worth of PBW cleaning solution from a keg, and again letting it sit for a couple of minutes before flushing it with a few bottles of fresh water, also from a keg. Cleaning and sanitizing is a pretty simple operation, but it does require that you have a spare keg around for sanitizing solution, cleaners, and fresh water to rinse.
Summary:
Wensel's Counterpressure Filler seems to be well designed and constructed. It has done a good job by my observations, and a few easy and inexpensive user-performed modifications make it even better. It is easy for one person to perform a filling and capping operation by him or herself, especially if you can mount it or clamp it to a sturdy surface. On the other hand, I have used a hand-held homebrew CP filler (Phil's CounterPhil), and it was a pain in the rear-end to use, even for two people, and almost impossible for one person alone to both fill and cap efficiently.
The Wensel costs $250 new, which is more than twice what any of the hand-held CP fillers will cost you...but it's also half of what the Melvico CP filler used to cost (when you could buy them). Considering the Wensel's good performance (not quite as fast a filler as the Melvico, though, and it doesn't gas or fill from the bottom of a bottle), my cost/performance analysis would lean slightly in favor of the Wensel filler versus the Melvico. Since we're usually not bottling for commercial sale, slightly slower performance shouldn't be a deciding factor.
Buying Recommendations: If you can find one either new or used (good luck!), and money is no object, get a Melvico. Otherwise, I don't think you'll go wrong with the Wensel. If cost is a major consideration (e.g. $90 for a handheld vs. $250 for the Wensel), get a hand-held model...in my searches the one I liked the best was sold by www.hoptech.com. But having said that, I also think that ease of use is worth something, I've already owned a Phil's CounterPhil...and sold it after using it just one time. For the extra money, I believe the Wensel will serve you better in the long run than a less expensive, hand-held filler.
The Melvico seems like it's built more robustly than the Wensel. But when you put the Wensel to use, although it is very lightweight it does not feel flimsy. Just affix it to a solid surface for stability and easy, one-handed operation. As for its long-term durability, I don't know what it will look or perform like in a year, or two or ten. You might want to consider getting a few extra replacement parts now, just in case. But so far, it has filled about 650 bottles with no component failures. Seems reliable to me.
Steve Kranz
