Question on Lactic Acid

[swanco81]

I had a question about controlling the lactic acid component of my beer and what are some of the variables I can keep an eye on. Recently I brew a Weissen and it started off smelling slightly eggy in the fermenter, which when away before I put it in the secondary. I understand that typical for wheat beers. The problem of lactic really never surfaced until it had been in the keg for about a week. I could tell after a few days that it was starting to get a bit sour and it progressively did for about 10 days and now has kind of plateaued. It is by no means undrinkable and I know there is a lactic component in a Weissen, but I would like to have a little more control over the matter.

[brew captain]

Swanco,

Lactic acid is not known to be produced in large concentrations by brewer's yeast strains. It is normally produced by stains of lactobacillus which could indicate a contamination if you did not put it in there on purpose. I think you could be sensing the tartness that comes from beers with a lot of wheat in them. I think that beers with over 50% wheat have a distinctive tang about them. Not my favorite flavor compound and the reason I never go with more than 35% wheat in my recipes. Opinions may vary.

Oh, the other observation I had is that "eggy smell". Lager strains put out a lot of sulfur compounds, but not wheat strains. They are known to be vigorous fermenters that can finish after only a few days, but not sulfury in my experience. That also could be an indication of contamination, possibly some wild yeast got in on the action...

Would be interested to know more about the recipe and process...


Cheers!

[backyard brewer]

I'm on the same page as The Major, er uh.. Captain...

I think you may have experienced an infection, not normal flavors from hefe-type yeast.

[swanco81]

Thanks a lot guys. That is kind of what I figured, but I was interested in other input because I've never had contamination issues for the last 20-30 batches. I guess the issue was bound to show it's ugly face again. Here is a quick description of the recipe.
5 gallons
Wheat Malt 66%
Pilsener 2row 32%
Crystal 30 2%

Hallertauer .5 oz 60 min
Hallertauer .25 oz 30 min

Wyeast Bavarian Wheat #3638

Mash Schedule:
Quite a thin mash 1.8 qts/lb.

Protein - 122F target, 135 achieved, 30 min

Decoction- Remove after protein 40% of mash, Raised to 152F held for 15mins, Then boiled for 20 min.

Recombine with Mash to yield 147F rest for 15 min.

Raise to 158F 45 min.

No mash out just a sparge with 170F

Fermentation schedule:
10 days in primary @ 65F (after about six days the egg scent remained, waited another few days until it disappeared)

10 days in the secondary same temp. At this point it tasted awesome.

Keg for a week before it started to get a little lacticy, progressively got worse for a few days and has maintained that flavor.

Notes:
SG 1.047
FG 1.010
SRM 5
IBU 11.2

The keg had had root beer in it prior. It was cleaned extensively with hot iodine mixture.

All equipment cleaned with caustic acid and sanitized with a heavy sanitizing solution(forget all the compounds)

I guess that is a little more than a quick description.

Proost!!

[brew captain]

Well the only thing that caught my eye was the "hot iodine solution". If you were using iodophor then it is not supposed to be used with hot water. That will reduce or completely eliminate its effectiveness. That could have left your keg less than optimally sanitary explaining why the sourness started to develop after kegging.

Just guessing...


Cheers!

[BrewMasterBrad]

The keg had had root beer in it prior. It was cleaned extensively with hot iodine mixture.

All equipment cleaned with caustic acid and sanitized with a heavy sanitizing solution(forget all the compounds)

Iodine is not a cleaner. Hot iodine is less effective than room temp idodine. That may be your problem. If I ever have kegs that were previously used for soda, I replace all the rubber o-rings, clean with hot PBW, then sanitize with StarSan.

[swanco81]

Thanks for the reply. That is usually the process i go through to clean the kegs, but didn't have that opportunity at the time. The keg was clean or so I thought, it just needed to be sanitized.