Infection after 3 months in two batches

[sqrt3]

In the end it happened: after 5 years of homebrewing, my beer got infected.
The problem is that I really cannot understand how and why. I am always careful, almost paranoid with cleaning, but this seems a really strange infection.

I made 2 batches in parallel, a white IPA and a black IPA, partial mash method.
They fermented without any problem, 10 days in primary 1 week in secondary with DH and then I bottled everything.
After 1 month up to about 3 months after bottling I was drinking both beers and they were very good, the black IPA seemed to taste better and better.

Suddenly, in the third month, the flavor has changed strongly in both beers with heavy acetic flavor and now it is practical to throw away (30 liters...).

I'm trying to understand how it is possible, given that:

• I had no problems with fermentation (10+7 days, 20 °C constant temperature, cold crash at 8 °C, clean wort, FG as expected)
• at the beginning the beer tasted really good and the infection occurred after about 3 months, even in the presence of high alcohol (7.6 ABV)
• the infection caused strong acetic flavors, lots of foam, but no strange residue on the surface of the bottles and very clear beer (white IPA)
• the infection concerns both batches (of course I used the same stuff in brewing and bottling)
• I used my own hops, in wort and in dry hop (not the first time)
• I used for the first time Mangrove Jack's M44 yeast in both batches
• the infection is present in all the bottles (carefully cleaned)
• the bottles were in cellar, at cool temperature (14 °C) all the time

I cannot explain why everything occured after some time and on both beers. I tasted an infected beer from a friend: it was strange before bottling, and it was undrinkable after 1 month.

Does anyone have any ideas on how this could have happened, so as to avoid mistakes in the future?

Thanks

 

[RM-MN]

In the end it happened: after 5 years of homebrewing, my beer got infected.
The problem is that I really cannot understand how and why. I am always careful, almost paranoid with cleaning, but this seems a really strange infection.

I made 2 batches in parallel, a white IPA and a black IPA, partial mash method.
They fermented without any problem, 10 days in primary 1 week in secondary with DH and then I bottled everything.
After 1 month up to about 3 months after bottling I was drinking both beers and they were very good, the black IPA seemed to taste better and better.

Suddenly, in the third month, the flavor has changed strongly in both beers with heavy acetic flavor and now it is practical to throw away (30 liters...).

I'm trying to understand how it is possible, given that:

• I had no problems with fermentation (10+7 days, 20 °C constant temperature, cold crash at 8 °C, clean wort, FG as expected)
• at the beginning the beer tasted really good and the infection occurred after about 3 months, even in the presence of high alcohol (7.6 ABV)
• the infection caused strong acetic flavors, lots of foam, but no strange residue on the surface of the bottles and very clear beer (white IPA)
• the infection concerns both batches (of course I used the same stuff in brewing and bottling)
• I used my own hops, in wort and in dry hop (not the first time)
• I used for the first time Mangrove Jack's M44 yeast in both batches
• the infection is present in all the bottles (carefully cleaned)
• the bottles were in cellar, at cool temperature (14 °C) all the time

I cannot explain why everything occured after some time and on both beers. I tasted an infected beer from a friend: it was strange before bottling, and it was undrinkable after 1 month.

Does anyone have any ideas on how this could have happened, so as to avoid mistakes in the future?

Thanks

The red indicates the most likely area although it could have happened during bottling. You have bacteria in the air. All of us do, but most times the CO2, acidity, and alcohol combine to restrict their propagation. When your beer is in primary with a lid and airlock it has a covering of CO2. Moving it to secondary leaves this behind and now you have oxygen in that airspace above the beer, oxygen that acetobacter needs to propagate. Acetobacter likes to eat alcohol and excrete acetic acid, the vinegar taste you found. It could also get a start when you open the fermenter and transfer the beer to bottling bucket but this isn't as likely as when you add the priming sugar and bottle the beer the yeast scavenge the oxygen quickly and leave CO2 inside the bottles.

For your next batches, leave the beer in the primary until ready to bottle. Only open the lid enough to fit the siphon and put a lid on your bottling bucket as soon as the siphon has started (loosely) to avoid as much bacteria as possible from settling out of the air. Don't delay any more than necessary when bottling.

 

[SlanginDueces]

I would change out all plastic/tubing you have on the cold side. Both batches indicates it was something you ran both beers through like maybe a bottling wand. After years of use things like that and tubing get scratches that can’t be sanitized.

 

[pdxal]

Bottling bucket spigot is another possible source.
Have you taken apart the spigot to clean and sanitize?

 

[sqrt3]

I did like always: I cleaned the fermenters, spigots, gaskets, bottling wand, etc... I washed and cleaned everything the day before with bleach solution and then with potassium metabisulfite just before using them.

It seems very unlikely (but not impossible, agree) that both the batches got infected in secondary. And I always put a lid on fermenter during bottling.
Moreover, the yeast seem to have worked properly in the bottle, I had good carbonation after few weeks with no strange off-flavors.

Maybe the problem could be my own hops added for DH, somehow infected?

 

[JamieGalea]

In the end it happened: after 5 years of homebrewing, my beer got infected.
The problem is that I really cannot understand how and why. I am always careful, almost paranoid with cleaning, but this seems a really strange infection.

I made 2 batches in parallel, a white IPA and a black IPA, partial mash method.
They fermented without any problem, 10 days in primary 1 week in secondary with DH and then I bottled everything.
After 1 month up to about 3 months after bottling I was drinking both beers and they were very good, the black IPA seemed to taste better and better.

Suddenly, in the third month, the flavor has changed strongly in both beers with heavy acetic flavor and now it is practical to throw away (30 liters...).

I'm trying to understand how it is possible, given that:

• I had no problems with fermentation (10+7 days, 20 °C constant temperature, cold crash at 8 °C, clean wort, FG as expected)
• at the beginning the beer tasted really good and the infection occurred after about 3 months, even in the presence of high alcohol (7.6 ABV)
• the infection caused strong acetic flavors, lots of foam, but no strange residue on the surface of the bottles and very clear beer (white IPA)
• the infection concerns both batches (of course I used the same stuff in brewing and bottling)
• I used my own hops, in wort and in dry hop (not the first time)
• I used for the first time Mangrove Jack's M44 yeast in both batches
• the infection is present in all the bottles (carefully cleaned)
• the bottles were in cellar, at cool temperature (14 °C) all the time

I cannot explain why everything occured after some time and on both beers. I tasted an infected beer from a friend: it was strange before bottling, and it was undrinkable after 1 month.

Does anyone have any ideas on how this could have happened, so as to avoid mistakes in the future?

Thanks

Hi

I have had exactly the same problem in my last 2 batches......

Did you find what was the cause and the solution to it?

I would appreciate if you share it with me because it is literally what has happened to me.

Thank you.