I have two gas tanks for my kegerator. This way I can be sure that I always have a backup. Both tanks are 75% nitrogen but one is a 20 litre tank and the other is 40 litres. The supplier I get my gas from does exchanges rather than refills. My thought process was that if I needed a replacement fast and my supplier had a 20 litre tank but not a 40 litre (or vice-versa) then I would still be able to make an exchange. I expected the only difference between the two tanks would be how long they last. But after switching back and forth between the two tanks, I’m not so sure. Here are my observations.<\/p>\n\n\n\n
I’ve written a bunch about having to adjust the PSI on my kegerator. I thought it might vary by keg but now I wonder if it varies by size of tank. I find that with the larger, 40 litre tank I prefer my PSI lower (around 30-35) and with the lower 20 litre tank I prefer my PSI higher (around 35-40).<\/p>\n\n\n\n
Even with a lower PSI, I find that the 40 litre tank results in a pour with a larger percentage of head. The 20 litre tank would almost always look like a pour that I would be happy to get in a bar. The 40 litre tank – especially without enough time to settle – will result in a pint that might get sent back if it were served at a real bar.<\/p>\n\n\n\n
I think that the smaller volume (20 litre) tank is more forgiving. You can get a good looking pour out of it at almost any reasonable PSI. Ditto for taste. I feel like you lose some complexity but gain some room for error. In other words, the Guinness will taste good within a wider range of PSI values. I think it is more important to dial in your PSI with the larger tank. I’ve found the optimal PSI to be similar to coffee grind size. By that I mean that it is not a linear progression where you can just keep adjusting one way until you find what you like. There’s a range in the high 20s and low 30s that can be good. And a range in the upper 30s that can be good. But the values in between are worse.<\/p>\n\n\n\n
I think I prefer the larger tank. Part of that is because it lasts longer. Not just because there is more volume but also because I tend to run it at a lower PSI. Another part is that I feel like I can get a little extra creaminess out of it. The smaller volume tank feels a little more homogeneous. If I adjust the PSI too low it just tastes bad. With the larger volume tank I can go a littler lower on the PSI and try to introduce more perceived creaminess.<\/p>\n\n\n\n
I considered whether the differences I’m perceiving are just due to using different tanks and nothing to do with the size of the tanks. But I’ve now used each size of tank multiple times. Because I am exchanging the tanks, it is unlikely that I have used the same 20 litre tank or the same 40 litre tank. Yet the behavior is the same. I wish there were a way for me to better test this. I don’t know enough about gas to design a test. I would love to do a blind tasting. But I assume that if I switched out a gas tank between pours then the keg would retain some residual gas from the first tank. But if I had two different kegs (and two different kegerators) then any perceived difference might not be attributable to the different sized gas tank.<\/p>\n\n\n\n
This is just something I will need to keep an eye on. I just switched to the 40 litre tank so it will be a while before I switch back. Part of my reason for writing this all down is so that when I switch back to the smaller tank I can see if I have the same observations.<\/p>\n","protected":false},"excerpt":{"rendered":"
I have two gas tanks for my kegerator. This way I can be sure that I always have a backup. Both tanks are 75% nitrogen…<\/p>\n