Anyone notice diacetyl from Big dry hopping?

Didn't know that. Thanks.

Bamforth and Kanauchi report an optimum pH of 3.5 for an acetoin dehydrogenase enzyme isolated from a commercial lager yeast strain, suggesting that diacetyl reduction rates are higher at lower wort pH values (i.e. towards the end of fermentation). Several sources report an increased reaction rate for the oxidative decarboxylation of α‐acetolactate to diacetyl at lower pH values, which also suggests that the rate‐limiting conversion of α‐acetolactate to diacetyl is faster at more acidic wort conditions. The maturation time needed for diacetyl reduction could thus be reduced at lower beer pH values, as long as the pH stays within the range that is suitable for a palatable beer. The pH of beer is typically in the range of 4.0–4.5 but can vary from around 3.7 to 5.0 depending on style and ingredients. ^ link ^

Dry hops are known to raise the pH. I add some acid to the keg while dry hopping big. This is done for flavor purposes, but it might have unknowingly helped prevent diacetyl. I prefer citrus/fruit bomb IPAs to be more acidic than traditional IPAs. 1098 is a yeast I often use for these beers. It produces more lactic acid and a lower pH than most Sacc.

That doesn't explain the lack of re-fermentation I experienced. As @checktherhyme suggested, the high flocc might help prevent it. 1098 floccs fast and clear. Strangely, dry hopping clear finished beer made with 1098 will reliably produce thick permahaze.

I suppose it's possible the hops cleaved some dextrins and the yeast did not ferment all of the new sugar which resulted in the same FG as before dry hopping.

 

That's possible. However, there are other yeasts that drop clear before getting a big load of dry hops that do not produce low yeast gravy beer like 1098 does. 1318 does the same thing as 1098, but it takes longer to clear before the dry hop.

1728 and Omega DIPA (conan) don't produce gravy beer with the same process and dry hop amount (6-9oz). They produce a light haze that isn't gravy beer. They can produce gravy beer if the hops are added during fermentation, but I don't use that process often. I prefer to dry hop fairly clear beer.

 

Homebrewed hundreds of dry hopped batches. Never noticed a diacetyl issue. Maybe I suck at sensing diacetyl? I've observed diacetyl with homebrew using wy1968 for an ESB. It was butterscotch beer. It did not have dry hops. I've observed various levels of diacetyl in maybe 20-30 pro beers, but none of them were as strong as my butterscotch ESB. I think I can sense diacetyl well enough to know it's there.

My dry hop process is simple. My O2 mitigation process is simple. There are certainly more anal methods that people use. I've used many of them out of curiosity and didn't notice a significant improvement. YMMV

Fermentation - Removing the lid is forbidden. I don't dry hop the primary. I take one gravity sample from a spigot when I know the beer is done. I use a high flocc yeast such as 1098. It gets fermented cool and hit with some 70-75F heat on day 5 for a couple days. Then it's done. The heat belt is pulled and it returns to 60F for a soft cold crash. Clear beer gets kegged on day 10-11.

Transfer - Completely closed CO2 transfer into a purged keg is ideal. However, I sometimes let the fermenter drain into the purged keg via gravity. O2 is filling the fermenter headspace through the blowoff tube during the transfer(oh no). It turns out, this does not seem to be less effective than a completely closed transfer. When the beer in the keg is ~1/2 gallon from the top, I proudly open up the keg and dump some hops and citric acid. 1-3 minutes later, when the keg is full, I put the lid on and purge the keg.

Dry hopping - Free pellets are dry hopped at 60-70F under pressure. 20-30psi. 4-5 days.

Serving - The warm CO2 infusion cuts down on the amount of time needed to cold carbonate. The beer is served in the same keg with all the dry hops through a floating dip tube with a 300 micron filter. The beer is ready to drink after 7 days of cold carbonation at 34F. This process typically produces a hoppy beer that remains potent for more than 1 month. After that, it still tastes good.

 

Oh no, Billy. It appears you are still clinging to a deep seated resentment from years ago. It's OK, dude. Just let it go...

If you re-read the thread, you should notice that I'm very interested in hearing answers while providing likes or replies to the most relevant answers.

You are simply complaining and calling me names without proper justification. That contributes nothing worthwhile. You might be able to redeem yourself by sharing your experience regarding BIG dry hopping and how it relates to diacetyl or over attenuation.

Cheers!

 

We experience the opposite things with similar processes.

For example, "muddled" hop flavors aren't a common problem when I dry hop the keg. It doesn't matter if I leave the beer on the hops for a month or transfer to a serving keg. Muddled hop flavors are more likely to be a problem for me when I dry hop the primary, especially before the 5th day.

My current process is low tech, cold side semi-lodo. I've used every method I can think of including full hot side and cold side lodo. My current method consistently makes hoppy beer that retains plenty of hop flavor and aroma before the keg kicks which happens about a month after it's tapped.

Are you sure you aren't susceptible to Expectation Bias? I used to get fooled by Expectation Bias. "Advanced brewing techniques that make sense should taste better" is where Expectation Bias originates. Try to become oblivious to the science bias and trust your palate.

 

This beer inspired the comments ITT:

Viking Pale Malt (61%)
Viking Golden Malt (31%)
Gambrinus Honey Malt (2%)
Viking Cookie Malt (2%)
Hawaiian Turbinado sugar (4%)

Sorachi Ace - 1oz - 30min
Citra - 1.5oz - 10 min
Citra - 1.5oz - 5 min
Citra - 3oz - steep for 10 min
Vic Secret - 1oz - steep for 10 min

Dry hop in the keg
Vic Secret - 4oz
Citra - 4oz

Yeast - wy1098

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Citra has high enzymatic potential. Vic Secret's enzymatic potential is unknown, but it's sister Galaxy is similar to Citra. Cascade has low enzymatic potential. It was the hop OSU used to determine Big dry hops can create a significant quantity of new fermentables, which can cause late diacetyl production and or over attenuation.

As far as I can tell, I should have experienced some hop creep from this beer that was dry hopped in the keg at 64F for 4-5 days. There was no diacetyl. The finished beer has the same FG before the dry hops were added.