ChickenHops
Well-Known Member
I went overboard on my hops buying last fall (12 lbs, 10 varieties). I quickly realized that I needed a way to extend the shelf life as much as possible, especially after opening a bag for the first time. After some experimentation I settled on purging the original bags with nitrogen (they're also stored in a freezer). I don't have any empirical evidence regarding how well N2 purging works, but the cost is pretty minimal and the process (now that I have it down) is pretty effortless.
Some background regarding cost. I bought an extra 20# CO2 tank off craigslist last fall. The seller also had a CO2 regulator. The gauges were broken. The seller also had a second tank. It turned out to be nitrogen.
I replaced the gauges in the regulator and had a complete (second) CO2 system. The CO2 tank was nearly full. The whole setup set me back less than $50. At the time the N2 tank was an afterthought.
The N2 tank was empty. I swapped it for a full tank. Cost to fill was $15. It should last me forever. I had to buy an adapter to use the CO2 gauge on the N2 tank. Cost for the adapter was around $15.
I already had some compressor accessories, including a hand valve with a needle valve. I used that with an air compressor to fill kid's basketballs, footballs, etc. Here's what my sub-$50 "purging station" looks like:
Here's a closeup of the hand valve with needle valve. I think around $10 at most hardware stores.
I try and work with hops bags in an area separate from where I grind grains, brew, etc. I'm not sure if it matters, but I feel that handling hops away from those areas whenever possible reduces the chance of contamination (especially is important if the hops might be used for dry hopping). When I open a large hop bag I only take out what I think I'll use over the next month or so. I cut a large corner of the bag to remove the hops. (this process also works for one pound bags of pellets)
Initially I used an iron to seal up the mylar bags. I discovered that hair straighteners work even better. Found the one below at Goodwill. $2
After removing the hops that I need I seal the large opening so that only a small opening remains. Doing so makes it easier to fill and purge the bag. If the opening is too large, it allows air to flow back in the bag after purging, or bits of leaf hops to blow out of the bag when purging. If the hole is too small it takes too long to purge the nitrogen. I found that a 1/4 to 1/2 inch opening is about right.
Next I place the needle valve in the small hole and fill the bag with nitrogen.
Once filled, I purge the bag by squeezing. I've even put the bag under a pillow or a large book to get out nearly all the air. I'm not sure how critical it it is to purge all the gases, but the more you purge the less room the bag takes up in the freezer.
Again, having a smaller hole prevents air from being sucked back into the bag once I remove the pressure. I perform a fill and purge 3 or 4 times. I'm not sure how much O2 is left in the bag. I hope it isn't a lot. (Sometimes I wonder if this is all a waste of time, but common sense tells me it makes a difference. And it really doesn't take that much effort.).
As a sidebar, the hop aroma is (or should be) pretty strong when you purge the bag. A good sniff gives a good indication of the different aroma characteristics in different varieties.
After the last purge I seal the remaining small hole. On the final purge I'm particularly careful not to allow any air back into the bag.
I store hops in the original bags as much as possible. I also have a vacuum sealer which I use. My initial plan was to repackage all the hops into vacuum bags. However, after doing this with one bag (which had 20 oz of hops) I found that the vacuum bags took the same or more freezer space than the original mylar bag. Plus, vacuum bags are costly and filling them with hops is a bit of a pain.
My N2 filling (and purging) process took a little while to refine. It now takes very little effort. For people who already have a CO2 system all you need is an N2 tank and adapter, as long as your regulator can handle the higher pressure of N2.
I wont' know for a while how long hops will last using this process. I can say that bags that I first opened and resealed 6 months ago still seem as fresh as the day I first opened them. It's nice to have plenty of quantity and variety on hand at all times.
BTW, nitrogen isn't just handy for brewing. I even use it to top off the (N2 filled) tires on my car when they get low.
Some background regarding cost. I bought an extra 20# CO2 tank off craigslist last fall. The seller also had a CO2 regulator. The gauges were broken. The seller also had a second tank. It turned out to be nitrogen.
I replaced the gauges in the regulator and had a complete (second) CO2 system. The CO2 tank was nearly full. The whole setup set me back less than $50. At the time the N2 tank was an afterthought.
The N2 tank was empty. I swapped it for a full tank. Cost to fill was $15. It should last me forever. I had to buy an adapter to use the CO2 gauge on the N2 tank. Cost for the adapter was around $15.
I already had some compressor accessories, including a hand valve with a needle valve. I used that with an air compressor to fill kid's basketballs, footballs, etc. Here's what my sub-$50 "purging station" looks like:
Here's a closeup of the hand valve with needle valve. I think around $10 at most hardware stores.
I try and work with hops bags in an area separate from where I grind grains, brew, etc. I'm not sure if it matters, but I feel that handling hops away from those areas whenever possible reduces the chance of contamination (especially is important if the hops might be used for dry hopping). When I open a large hop bag I only take out what I think I'll use over the next month or so. I cut a large corner of the bag to remove the hops. (this process also works for one pound bags of pellets)
Initially I used an iron to seal up the mylar bags. I discovered that hair straighteners work even better. Found the one below at Goodwill. $2
After removing the hops that I need I seal the large opening so that only a small opening remains. Doing so makes it easier to fill and purge the bag. If the opening is too large, it allows air to flow back in the bag after purging, or bits of leaf hops to blow out of the bag when purging. If the hole is too small it takes too long to purge the nitrogen. I found that a 1/4 to 1/2 inch opening is about right.
Next I place the needle valve in the small hole and fill the bag with nitrogen.
Once filled, I purge the bag by squeezing. I've even put the bag under a pillow or a large book to get out nearly all the air. I'm not sure how critical it it is to purge all the gases, but the more you purge the less room the bag takes up in the freezer.
Again, having a smaller hole prevents air from being sucked back into the bag once I remove the pressure. I perform a fill and purge 3 or 4 times. I'm not sure how much O2 is left in the bag. I hope it isn't a lot. (Sometimes I wonder if this is all a waste of time, but common sense tells me it makes a difference. And it really doesn't take that much effort.).
As a sidebar, the hop aroma is (or should be) pretty strong when you purge the bag. A good sniff gives a good indication of the different aroma characteristics in different varieties.
After the last purge I seal the remaining small hole. On the final purge I'm particularly careful not to allow any air back into the bag.
I store hops in the original bags as much as possible. I also have a vacuum sealer which I use. My initial plan was to repackage all the hops into vacuum bags. However, after doing this with one bag (which had 20 oz of hops) I found that the vacuum bags took the same or more freezer space than the original mylar bag. Plus, vacuum bags are costly and filling them with hops is a bit of a pain.
My N2 filling (and purging) process took a little while to refine. It now takes very little effort. For people who already have a CO2 system all you need is an N2 tank and adapter, as long as your regulator can handle the higher pressure of N2.
I wont' know for a while how long hops will last using this process. I can say that bags that I first opened and resealed 6 months ago still seem as fresh as the day I first opened them. It's nice to have plenty of quantity and variety on hand at all times.
BTW, nitrogen isn't just handy for brewing. I even use it to top off the (N2 filled) tires on my car when they get low.
