nitrogen dosing

[beerdude8]

Does anyone know anything about nitrogen dosing bottles to purge them of air? Dose it work?

[Valleybrew]

Yes nitrogen dosing will reduce Oxygen levels if done correctly but so does CO2 and its probably cheaper for you.

[Rob Creighton]

Re: Nitrogen Dosing?

Are you refering to the pre-fill dosing where the evaporating nitrogen displaces air in the bottle or post-fill dosing where the nitrogen replaces your water fob to limit head space airs?

Both can do their respective jobs well but the beer entering the filler (tank airs) must still have zero air to begin with (this is the biggest problem I observe at smaller bottling operations - not knowing the state of the product entering the bottle - filtration problems, pump seals, etc... often contribute most of the air).

Depending on your equipment, achieving a target of less than 1ml of air (ideally <.5ml) and a DO of less than .25ppm consistently is done everyday on older, non pre-evac equipment. I have not used nitrogen myself but some friends have and I will check with them for specs and performance (One problem they have is that they don't check tank airs with regularly calibrated equipment so I will suggest to take it with a grain of salt). From watching it run (post-fill), it seemed to offer fairly consistent and problem free operation.

[MikeJordan]

Yes nitro drip systems work. You may be able to find a used one from a mid-sized micro. that has recently purchased a new bottling line. A new nitro drip system is very expensive and you still have the cost of the continuous use of N2. (One brewery I worked for in the mid 90's actually found a company that would lease one to us and charge us on a per unit basis.) Depending upon the machine you're running you should be able to achieve acceptable air levels at or below 1.0 ml configuring a CO2 purge/evac from the bottle. Yes this can even be achieved with old Meyer's fillers. Checking DO levels throughout the cellar is great but most small brewers cannot afford a $5k Orbisphere. I think if you pay close attention to your equipment and purge all lines/tanks you may be able to avoid this costly investment until you reach the appropriate size and sales area. Consequently I was once told by a Zahm representative that when checking headspace air the first gas relief and corresponding reading is actual headspace. The difference between your first and second gas relief reading is generally your dissolved Oxygen reading. Of course the second reading is still the total headspace air. Good luck!

[jrdamas]

Mike,
The brewery I work for was able to find a slightly used Linerter System from a juice packing plant. It works great! Once a the bottles are rinsed a drop of LN2 evaporates in the bottle and seems to purge out air very well. The bottles then reach the filler where they are pre-evac. with CO2 before filling. The major operating cost is the purchase of a dewar of LN2 for ever bottling session (I think its about $200 in our area). Since LN2 needs to be vented at all times you cannot have extra tanks of Ln2 on hand for an extended period.
J. Boy

[MikeJordan]

Hopefully this info will help beerdude. Not sure if it's just me or what but the combination of LN2 and CO2 pre-vac seems a bit overkill and somewhat costly. My experience has been that a brewery will usually use LN2 when they have no pre-vac capabilities or don't want to invest in a spendy pre-vac system for "antique" equipment. Perhaps this is one instance where it seems to work for you so why change? I think long term CO2 is the way to go and it's also a gas source that is already on site.

M.J.

[Rob Creighton]

I could still see using nitro-drop as a post-fill replacement for fobbing if you had a pre-evac filler. Pre-evac does virtually nothing for head space airs and you could save the beer lost with an inconsistent/improperly setup water fobber let alone get rid of the water contamination concerns. How many lowfills have you created by messing around with water jet fobbing over the years? Every style of beer fobs differently depending on viscosity and carbonation and nitro provides a path to a much more consistent start up when you are bottling multiple styles. I hated switching from stout to lagers because all of the fine tuning required at the filler.

[Rob Creighton]

And Mike:

We never had an analytical tool to measure DO (corporate decision). We used the Zahm bottle we purchased with the CO2 tester and used the tank air data as a measuring point for air performance on our brand new single pre-evac Krones filler/crowner. If a filtration or delivery system failure contaminates your product on route, you will never recover shelf life with a wonderful piece of German technical genius. There is always more than one way.

[MikeJordan]

Rob,

I think the idea of using LN2 for fobbing is interesting. Unfortunatley I have not seen any other breweries using this approach. I saw a LN2 equipment setup at a CBC expo several years ago. While working for a small brewery at the time we were very interested in this for reducing our total headspace air levels. The cost of this aftermarket equipment was something around $10K. This equipment price coupled with the additional gas cost was not in the budget. Having talked with several equipment manufacturers and equipment brokers we were told that we had two options to reduce air levels. LN2 or a pre-vac system. Neither was in the budget but the double pre-vac system seemed like the best long term investment with gauranteed results. Contrary to what we had been told we made some changes to the filler and the CO2 purge and drastically reduced our total headspace air levels to 0.6 ml. Luckily I had a DO meter to backup my work and prove that our DO levels before packaging were 0.100 ppm and lower (all the oxygen was coming form the filler) It was a very effective method for us and cost 1/100th the price. So I would agree with your response--Yes there are several ways to accomplish the same goal. Therefore I like to share this experience with other brewers that may be stuck in a similar situation--just take a scientific approach to any changes you make. Having said all this I think LN2 may help reduce air levels, but it seems like an expensive "bandaid" that may still need to be supplemented with other practices. In my current job we're very fortunate to have a nice Krones line with a double CO2 pre-vac system and sterile water fobbing. Our total headspace air levels are consistently below 0.10 ml and we have very few lowfills after a 500 bbl run. Yes I believe in German technical genius!!