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  • Narrow Serving Tanks

    So I am looking into purchasing three 15bbl single skinned serving tanks. Floor space is at a minimum but we can go up the way. The narrowest that I've seen is 110cm (43"). Does anyone know if you can get narrower or does it start to become a structural/top heavy issue? Thanks

  • #2
    The taller and skinnier you go, the more temperature stratification and reduction in convection will occur. Tall skinny tanks are not generally recommended. You will also see very increased settling times.

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    • #3
      +1 on all these points. I believe recommended ratio is 2:1 Height to Width.

      As an alternative you could consider stacking vessels that are short and long. Think lagering tanks. Shorter settling times, and you can still go high.

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      • #4
        Thank you for the advice. The idea was to shave off 5cm and thus give me just enough room to fit three in.

        Having lagering style tanks is a possibility. It would be interesting to see comparisons in CO2 pick up between vertical and horizontal.

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        • #5
          ok, i will once again stand up for the humble serving tank.


          temp stratification is a red herring. you serve from the bottom. unless your cooler's mechanical is crappy you should have fairly good consistency in temps near the ground and temps 10 feet up. the air needs to be moving. and not sure about your setup, but any long draft runs outside the cooler should be in a glycol trunk anyways so your final serving temp is dictated by that.

          if you worry about settling, you arent using finings, etc then you can always just filter. but it is a bit of a pain. thats dependent on how fast you're trying to turn things obviously, we've gone to finings almost exclusively with good results.

          our SVs are about 3feet wide for the tall skinny 15s. not sure they get much skinnier than that. but if you have free and clear space in front, you can always stagger them against each other.

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          • #6
            Originally posted by Hirsty View Post
            Having lagering style tanks is a possibility. It would be interesting to see comparisons in CO2 pick up between vertical and horizontal.
            You would find the lagering tanks should pick up co2 faster from head space (more surface area), however if using a carbstone there would likely be little difference if done properly. You will have the potential to see more aroma diffusion if going horizontal as there will be a much increased head space surface area. In other words, hoppy beers will loose aroma faster. Some will disagree. Cleaning can be a bit more cumbersome with horizontals as well, although not necessarily. Some I have seen now days use a bladder liner in the serving tanks and serve via air pressure to dispense beer without changing carbonation levels or losing aroma. Regardless of using finnings, the horizontals will still settle faster in the same conditions. Not usually an issue unless you are hard pressed for time often.

            To BrainMedicine's point, you would not be likely to see stratification make a noticeable difference in these size tanks, but it is a real fact in all tanks. I noticed it only to be significant in 30bbl or larger tanks, although I can see it happen in the 7's we have at our pub. Since the density of water is highest at 4*C (39.2*F), convection is important for getting below that point. That means your bottom of your tank is not the coldest point in most cases. Stratification of dissolved co2 will happen as well for these same reasons, but again not so noticeable until you get much larger. Again he is correct in saying you should have trunk lines chilled offering a perfect serving temperature (if not a direct draw through cooler wall).

            5cm of size difference shouldn't be enough to make much difference, however it may cost you a lot more in terms of manufacturing. Depends if tanks are prefabricated or not.bStaggering them would probably be your best option for cost savings in the end. Just make sure you have room to open your manway doors.

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            • #7
              "It would be interesting to see comparisons in CO2 pick up between vertical and horizontal."

              If you CO2 top pressure is in equilibrium with the dissolved CO2 in the beer, then surface area is irrelevant - so get the correct TP, temperature etc and you will not suffer CO2 loss or pickup.

              Re material savings - you probably won't save anything as the steel comes in standard size sheets, and if they have to cut those, then normally it costs more than if using a whole sheet, uncut. And particularly if they can't use the offcuts, then you are likely to be charged for the total materials used and wasted, not just the materials used to construct your tank.

              Personally, I hate horizontals, for rough beer in particular, as they are more difficult to clean due to poor scavenging, so use of high pressure jet heads and automated control of burst delivery cycles to optimise scavenging are preferred in any sized horizontal, but definitely required in big vessels (OK yours will be anything but big - but still can be a pig to clean)
              dick

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              • #8
                Originally posted by dick murton View Post
                "It would be interesting to see comparisons in CO2 pick up between vertical and horizontal."

                If you CO2 top pressure is in equilibrium with the dissolved CO2 in the beer, then surface area is irrelevant - so get the correct TP, temperature etc and you will not suffer CO2 loss or pickup.
                I was assuming the question was in relation to adding gas for carbonation purposes, not just pick up or loss from serving. In carbonating I would say the surface area is quite relevant to the time in which gas dissolves into the liquid. This is the main reason for carbonation stones, specifically to create more surface area to gas contact. If not using a stone, horizontals should carbonate faster by absorption of head pressure. It would not be a factor once the beer was carbonated, assuming equilibrium, but equilibrium is almost always in fluctuation on a serving vessel. As you serve the beer, you are changing the balance. Yes, the inlet pressure is re-equilibrating, but there is an amount of time in which this balance is not held. Some gas loss will occur. In smaller tanks this is more noticeable. For instance I cannot keep 7 bbl weizen in my serving vessels from loosing some (albeit a small amount) carbonation over the serving period. It moves fastest of all my beers at roughly 1-1.5 bbl per day. The majority happens in a 2-4 hour window. Keeping the co2 flow at 1 bar will not keep up with the rate of dispense. A higher inlet pressure would result in a change of draft line balance as soon as the serving stopped or paused(and ultimately pressure relief from the tank). In order to keep the gas filling at an appropriate equilibrium, I would need some pressure sensors and solenoid valves.

                Diffusion of aromas was the main point of the increased surface area mentioned. Bladder tanks eliminate any issues cleaning. I don't particularly advocate for the horizontals, but there are advantages to both designs. Settling times and aroma are the big two for me.

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                • #9
                  Have you not considered upping the flow rate to that tank, upsizing the co2 supply line and possibly the secondary regulator for that tank? Or maybe your entire supply header needs upsizing.

                  Maybe im missing some details but 7 is not very big and you should be able to supply nice even head pressure pretty easily id think. We have a 5 that gets about half emptied in a day for special events and stays plenty carbed. Only a 3/8 header supply.


                  As for bladders, the idea is interesting but haven’t seen them in US, only Europe. Would be interesting to see the economic of buying bladders vs typical cleaning and co2 push. Id think in SF it could be close comparison. Its high rent/labor/co2 area. But in Mexico the labor and co2 are cheap. Chems fairly cheap.

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                  • #10
                    Originally posted by brain medicine View Post
                    Have you not considered upping the flow rate to that tank, upsizing the co2 supply line and possibly the secondary regulator for that tank? Or maybe your entire supply header needs upsizing.

                    Maybe im missing some details but 7 is not very big and you should be able to supply nice even head pressure pretty easily id think. We have a 5 that gets about half emptied in a day for special events and stays plenty carbed. Only a 3/8 header supply.


                    As for bladders, the idea is interesting but haven’t seen them in US, only Europe. Would be interesting to see the economic of buying bladders vs typical cleaning and co2 push. Id think in SF it could be close comparison. Its high rent/labor/co2 area. But in Mexico the labor and co2 are cheap. Chems fairly cheap.
                    It's not really a problem, just a noticeable declination for me. Beer drops about one box, maybe two on the zahm chart over the serving of the tank (about 6-7 days). Noticeable to me, but no so much to the general consumer. Problem is because I am in a cold room and not jacketed tanks I can only really get up to about 2.8 volumes max (5.53 g/l if my brain calculator is working correctly) due to temperature limitations (3*C or 37*F). PRV are set at 1 bar, so I can't reach a higher equilibrium than that. 2.8 is the lowest end of what I really find acceptable for the style, so when it looses a little it bothers me on a personal level.

                    I use a high flow regulator to feed the 7 secondary (tap rite) regulators, but it is here the bottle neck occurs. The secondary does not have the volume flow at the desired pressure setting. Upping the pressure will balance the draw rate (we serve two restaurants with these SV's), but then it wastes gas once the draw stops (bleed off). Since Hefe has to go into the first available tank, it moves between the six and I cannot really afford to put in 6 high flow secondary regulators for one style of beer. (First they're not cheap, second I would probably have to fly them back in my suitcase). The best solution I can think of would be to add a gas buffer tank between the secondary lines and the serving tanks to buffer the rapid pressure drop. Space is an issue however. I just live with it. Point is, equilibrium is a "perfect" state that is rarely an actuality in serving vessels.

                    I have not seen the data myself, but a few people here (Bangalore) swear the bladders are cheaper when factoring chems, labor, co2, and time. I know Mexico is cheap for labor, but India can't be any higher. A skilled employee might see $3000 a year and the average per capita is $1600 annually. Average labor cost here is $0.94 per hour. Mexico is about double that average around $2 per hour (even at their all time low). Chems are relatively cheap here too. They manufacture more pharma products than China, and so base chemicals are in abundance. I'll ask the next time I meet one of these brewers as I am curious to see the cost of bladders and factor it myself. Of course this is something you would have to factor from the beginning.

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