Sudden Loss of Aroma with Dry Hopped PA in last few batches

[voltage]

Basically we First Wort Hop and Dry hop our Pale Ale to get a nice aromatic. I've just taken over the brewing and just can't seem to get the Aroma that the last brewer was able to.

There's a few variables I can think of. The recipes haven't changed, nor the hops;

-First, I wasn't doing my First Wort Hop additon early enough but after reading I should be adding them as soon as I start to fill the kettle with hot wort. I've made this change but won't know for a few weeks if it helped.

-Second, I have also done a more gentle carb process with a little head pressure (Where as the old brewer would just crank it up with no head pressure and not use gradual PSI Increases).

I have used the standard 60-80 ML of Nalco (Per 150L) and the beer is clearer than ever before, ...but the aromatic is basically a fraction of what it was. I did not scrub anything out of the brite tank.

Last variable is after the first week the batches get dry hopped and I usually give them a little stir in with some CO2 via a line and blow gun nozzle from a side port. Yesterday I decided to just leave the hops in the top of the ferementer and let them (hopefully) settle out over the next week.

Any suggestions and experience with a loss of aroma, or how you're able to get maximum aroma in your practices is greatly appreciated.

[william.heinric]

How's your yeast performance? Do you have data on attenuation, pH and temp?

In consultation with a regional friend, I discovered that I was stressing the yeast, and was able to increase our pre-DH aroma. Almost all of the DH flavors are either directly or synergistically influenced by the yeast.

Over-fining may also be trimming your aromatics. If your yeast is healthier, you may be able to get harder flocculations, and thereby reduce your finings.

That's where I would start.

Bill

[voltage]

"How's your yeast performance? Do you have data on attenuation, pH and temp?"

I've checked the Attenuation a few times, but will check on batches like this one to be sure they're bang on with our usual 1.010 FG. I have no records on our pH but can certainly gather some info on this and start to compare. The Temp I set to keep at 65f, our usual... however this time of year it's a bit cool, so in actuality I have a lack of ability to reheat and maintain a perfect 65f. 62-64 after the initial fermentation isn't uncommon, but there is some fluctuation in temp (Bad for yeast!).

In consultation with a regional friend, I discovered that I was stressing the yeast, and was able to increase our pre-DH aroma. Almost all of the DH flavors are either directly or synergistically influenced by the yeast.

I like where you're going with this. I have great flocculation on my first re-pitch after using Dry US-05 but by the time I go to do my second re-pitch I don't see much yeast at all, like it's stuck in suspension.

Over-fining may also be trimming your aromatics. If your yeast is healthier, you may be able to get harder flocculations, and thereby reduce your finings.
I'm not seeing hard flocculations on my 2nd repitch, (I only run 3 gens on the 05), My new carb process doesn't allow for much agitation of the yeast that settles in the brite tank either. I could try cutting the nalco out completely and see if the aroma comes back?

This is great advice! I'll see if I can get more heat belts to get us back to a constant 65 degrees after the cooling overshoots. I'll try to get some better flocculation or if not successful just run two generations for now, until this is resolved. I should also check our FG and PH levels and document/compare to previous, more aromatic batches to look for sings of trouble.

[anthonybaraff]

Oxygen pick up will destroy aromatics. Is it possible that something has changed with the way you are transferring to brite/service tanks or the way you are packaging?

[voltage]

Oxygen pick up will destroy aromatics. Is it possible that something has changed with the way you are transferring to brite/service tanks or the way you are packaging?

I got a crash course in this one but basically after sanitizing the brite tank and connecting everything back up I use c02 in the carb stone to build some pressure and then purge the 02 out of the tank via the relief valve on the top.

Brewery pump gets connected and I bleed of the first little bit until the pump is pumping only beer. Then I connect to the bottom of the Brite and gently do my transfer. Takes me about 10 mins to do 150 L. The ONLY way I could be adding oxygen in this step is the blow off hose starts to create a suction of air. The reaction to this is a normal positive pressure in the head of the brite which I bleed off slowly as needed but maintain 1-2 PSI. Should I be letting it suck in sanatizer instead of air?

The other spot we're trying to eliminate some oxygen is during kegging. The previous brewer didn't use the sight glass but my Boss and I like to see when the sediment starts to flow, but there's always a little airspace in the sight glass that I can't seem to get fully filled with beer. I think we're getting some 90 elbows to stop it from sitting level to try and eliminate this.

Could either of these be enough oxygen to support your theory?

[anthonybaraff]

Oxygen pick up will destroy aromatics. Is it possible that something has changed with the way you are transferring to brite/service tanks or the way you are packaging?

I got a crash course in this one but basically after sanitizing the brite tank and connecting everything back up I use c02 in the carb stone to build some pressure and then purge the 02 out of the tank via the relief valve on the top.

Brewery pump gets connected and I bleed of the first little bit until the pump is pumping only beer. Then I connect to the bottom of the Brite and gently do my transfer. Takes me about 10 mins to do 150 L. The ONLY way I could be adding oxygen in this step is the blow off hose starts to create a suction of air. The reaction to this is a normal positive pressure in the head of the brite which I bleed off slowly as needed but maintain 1-2 PSI. Should I be letting it suck in sanatizer instead of air?

The other spot we're trying to eliminate some oxygen is during kegging. The previous brewer didn't use the sight glass but my Boss and I like to see when the sediment starts to flow, but there's always a little airspace in the sight glass that I can't seem to get fully filled with beer. I think we're getting some 90 elbows to stop it from sitting level to try and eliminate this.

Could either of these be enough oxygen to support your theory?

I think your approach to purging your brite could very well be the source of your problem. I have a hard time picturing your setup though since I don't know if you have CCTs with a CIP valve in the top or what you are using for a brite with only 150l capacity. You should probably find out what your previous brewer was doing, though.

If you add 15 additional PSI to your brite to purge it you go from 23% oxygen down to 11.5% which will still destroy a beer in no time. I have to imagine that you have a lot of surface area in contact with the atmosphere inside the brite tank if we're only talking about 150 liters of beer. I'd open the CIP valve, and bleed in CO2 continuously until a reading from an oxygen meter below an acceptable level like 1%. Also, I'd hook up the blow off on your fermenter to your CO2 or the out of the CIP on your brite instead of sucking up all of that air. Are you purging the kegs before filling them?

[voltage]

I think your approach to purging your brite could very well be the source of your problem. I have a hard time picturing your setup though since I don't know if you have CCTs with a CIP valve in the top or what you are using for a brite with only 150l capacity. You should probably find out what your previous brewer was doing, though.
If you add 15 additional PSI to your brite to purge it you go from 23% oxygen down to 11.5% which will still destroy a beer in no time. I have to imagine that you have a lot of surface area in contact with the atmosphere inside the brite tank if we're only talking about 150 liters of beer. I'd open the CIP valve, and bleed in CO2 continuously until a reading from an oxygen meter below an acceptable level like 1%. Also, I'd hook up the blow off on your fermenter to your CO2 or the out of the CIP on your brite instead of sucking up all of that air.


I'll defiantly set up a long, steady purge with CO2 and error on the side of using more gas than needed. That's a great idea on charging the blow off line. I'll set it up with an auxiliary tank of co2 with a few PSI.

Are you purging the kegs before filling them?

After cleaning I fill each keg with 10 PSI of CO2 and then cool the kegs prior to filling.

When the old brewer went over the keg filling with me, once we opened the valve and beer started to flow we wait for about 10 seconds and then open off the blow off line and he would crank it wide open until the pressure dropped and the pitch changed and then we would leave with just a little hiss so we could hear when the beer started to flow.

On the other hand, during the last kegging session my boss didn't seem to think it was required to purge as much or at all. I was scared I would lose carbonation if I over purged so I split the difference and do about a 3 second partial purge but what is a good best practice? (Sankeys obviously)

[BemidjiBrewing]

I would heed Anthony's advice from above and do a thorough purge of the Brite tank prior to filling, plus leave a bit of positive pressure in the tank that can be bled off just prior to transferring.

As for keg filling - everything needs to be completely purged and pressurized with CO2, treat all kegs just like mini brite tanks. A simple blast of gas does very little to displace the amount of oxygen that may be in the keg. It all depends on how you clean your kegs, if you have introduced a lot of ambient air or compressed air into the keg during purging of ullage, cleaning, emptying, and sanitizing you will have that much more oxygen to purge out prior to filling. If you are manually purging your kegs with CO2 you definitely need to be purging down the spear and out the gas-side of the coupler until you achieve a strong aroma of CO2 or can verify with an O2 meter. This can take quite a bit more time than expected.

As for the bubbles in your sight glass during kegging - try rotating your racking arm to the upright position once the bright tank is full or prior to kegging, or even fill the tank with it in the upright position. This will allow it to fill completely with beer and not be a deadspot. Also, when you purge the tank with CO2 prior to filling it make sure you are purging the racking arm and any other ports that may be a potential deadspot for CO2 flow.

As per the original post, these points of oxygen ingress downstream from dry-hopping have a huge potential to be rapidly diminishing your hop aroma - not to mention the overall quality of the entire beer. Oxygen is the enemy and as small brewers we usually have to take extra precaution and steps to prevent its degradation of our products

Cheers,
Tom

[SPace]

Purge Everything Except Your Beer

After you fully purge your Bright Tank you can cap off the CIP arm and open the bottom valve to allow CO₂ to back flow through all your hoses.

Aim these hoses at the drain and let the CO₂ pressure push any residual water or sanitizer out, then cut the CO₂ and loosely hook the hose up to your fermentor, vent the CO₂ through the hose again allowing it to bleed through a loosely connected tri-clamp on the racking arm of the fermentor. This will purge your line of air.

As for kegging, you should treat each keg as a small bright tank. They all need to be fully purged along with filling lines.

Also, if you carbonate quickly without head pressure or bleed off head pressure, the CO2 will scrub your beer of Oxygen AND YOUR AROMATIC COMPOUNDS, so a bit of a double edged sword there.

[voltage]

This is all very helpful you guys! I have a lot of things to try now and perhaps all these best practices together will do the trick and then some. I like the back purging idea a lot too.

[voltage]

My aroma is starting to come back now that I have done basically all of these things. A proper brite tank purge (2x 15 PSI Charges and drains and then a slow release of Co2 at 5 PSI Head Pressure (20 PSI on the carb stone) for 6 minutes. I connected the fermenters blow off line to the CIP after the purge and also try to get as much o2 out of the pump as I can before a nice gentle transfer. Lots of purging of the kegs during initial filling as well. No fining agent used, beer is clear enough but aroma is more important than clarity. Oxygen is the enemy I can't see, yet is always trying to get in my beer. The war is on O2...