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I've never done a diacetyl test. Will do for the next brew.

I've been doing them for a while now after encountering some issues with a NEIPA that fermented out very slowly causing me to rush it into the keg before it had cleaned up the diacetyl.

Pretty easy to do; just take two samples of the beer in sealed containers (I use a couple of these) keep one cool and heat the other to 70degC and hold it there for 10 minutes (I do this on the hob by placing the container in a pan of water). Let it cool down again and then do a smell / taste comparison with the unheated 'control' sample to see whether there is any diacetyl present.
 
What would be the best way to dry hop after fermentation and keep the oxygen out?
This is my only weakness in my otherwise oxygen free system. I leave a small co2 pressure on, quickly dump them in, then go for 7 headspace purges at 30psi.
Others have concocted solutions using magnets, but I ferment in kegs so would lose too much volume this way.
 
What would be the best way to dry hop after fermentation and keep the oxygen out?

I have a conical fermenter with a pressure relief valve so I blow CO2 in through the outlet to create a blanket over the beer before opening the lid . I then toss the hops in, close it back up and close the outlet valve.

I know some people use magnets to hold a bag of hops above the beer and then remove the magnet on the outside of the fermenter to release the bag when they are ready to dry hop. That way they don't need to open the lid at all.
 
I have a conical fermenter with a pressure relief valve so I blow CO2 in through the outlet to create a blanket over the beer before opening the lid . I then toss the hops in, close it back up and close the outlet valve.

I know some people use magnets to hold a bag of hops above the beer and then remove the magnet on the outside of the fermenter to release the bag when they are ready to dry hop. That way they don't need to open the lid at all.

I don't have the luxury of one of those lol.

I am worried about when the hops make their way to the bottom, taking air with them as they go. Damn air!

I've yet to try the magnet idea - although I did read somewhere it's best to get the beer off the yeast before you dry hop. yada yada yada lol
 
I had thought about putting the dry hops in a clean vessel, purging and then transferring on top, but it's guesswork how much to purge. ugh
There's a table for this to take the guess work out. I thought about doing this, but purging the whole keg properly instead of just the headspace would use a huge amount of co2
 
Basically, air mixes with Co2 extremely quickly, but dissolves very slowly in the beer, so as long as you can reduce the headspace O2 within a reasonable time, you should be ok.
Yeah it does. But it's the same when you brim it with sanitiser and push that out (for different purposes)
That only uses the volume of the keg in co2 though. I suppose what you could do is use the magnet system to an almost full keg (with sanitiser/H2O), then purge that headspace (and consequently the hop bag too), then drain as normal to get a keg full of co2, then closed transfer the beer. Perfect.
 
I fermented mine and then did a diacetyl rest. The hops are suspended above the beer in a muslin bag and a weight from some scales in it, knocked the temperature down to 15 and then lowered the bag down so it’s submerged. I’m going to leave it for 4 days and then raise the bag before cold crashing.
Never tried it like this before. Have to see how it turns out..
 
Diacetyl typically tastes and smells buttery, maybe a little like buttered popcorn, and is produced by the yeast perfectly normally during the early stages of fermentation. Toward the end of fermentation the yeast cleans up the diacetyl and a warmer temperature can help with this. If you stop fermentation early then you might interrupt this clean-up and the diacetyl will then be present in your beer. The yeast will continue to clean it up but this might take a long time if the beer is stored cold. In secondary fermentation you will have another cycle. When dry hopping if the enzymes in the hops trigger further fermentation you even may get another cycle. The risk of diacetyl, as long as you don’t rush fermentation, is not high but it can and clearly does happen.

The idea of dry hopping at lower temperatures is two-fold; you minimise the evaporation of volatile aroma oils and you minimise the enzymes from the hops getting dissolved into the beer and breaking down the unfermentable long-chain sugars into fermentable sugars. On the other hand if you dry hop at lower temperatures you also reduce the ability of the yeast to clean up any residual diacetyl.

As often happens you try to do one thing and you compromise another.

I ferment warm, even through the dry-hop, and I allow plenty of time for fermentation but I’m not suggesting this is the right approach, it just works for me (so far! 😉).
 
I ferment warm, even through the dry-hop

Me too normally, however the problem I have is with NEIPA's, as you have to get the hops out after a few days and I don't want to open the fermenter. So I pressure transfer off the hops and bam. Diacetyl. Have you a way to stop this H?
 
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What about


Me too normally, however the problem I have is with NEIPA's, as you have to get the hops out after a few days and I don't want to open the fermenter. So I pressure transfer off the hops and bam. Diacetyl. Have you a way to stop this H?
If you are worried about leaving the hops in the beer and you pull the beer off too early then the yeast may not yet have cleaned up. If you then store that beer at a low temperature then the clean-up might take a very long time because the yeast will be almost dormant. You could try leaving the beer somewhere warm for a few days to allow the yeast time to clean up?
 
I think you may be right Stu.

The carbonation is my fault as I only put 1 drop in. I daren't put two in cos sometimes the crown caps won't take it.

The problem is I'm using Mangrove Jacks's ones, and apparently 1 drop is suitable for 375ml bottles, and 2 drops for 750ml bottles, but I have 500ml bottles. Ugh.

You're going to say boil some water and put some sugar in aren't you lol :laugh8:
Try batch priming mate and this issue goes away
 

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