Brewing on grain - is this a lacto infection?

[Tall_Yotie]

Been brewing for 15+ years, and this is a first for me, though I have seen it posted many times.
Following an old distilling recipe to see what it made; boiled water, dissolved sugar, poured into (sanitized) bucket. Added cool water, then put in sweet feed (corn, oats, wheat, and molasses blend for horses). Added yeast. Let it ferment on the grains. Smelled fine, did its thing, slowly fermenting away.
Week and a half later, this is what I have:

White film with small spherical bubbles captured. Looks pretty. Smells like someone's early attempt at a sour (little cidery, but prob due to age). Very pretty.
Is this a lacto infection? If so, do I just let it do its thing, I just sample it until it is at the right funk then transfer and crash it, or are there any concerns I should have?
I'd taste it, but not wanting to get into that sort of science experiment right before work!

 

[Abhishek Dewan]

Yes it seems so. Happens with on grain, at times desirable when making whiskey.

 

[Tall_Yotie]

Yes it seems so. Happens with on grain, at times desirable when making whiskey.

Figured as such!
Too bad I didn't get a decent gravity reading along the way, as I won;t really know the ABV now. Ah well, live and learn!

 

[IslandLizard]

Too bad I didn't get a decent gravity reading along the way, as I won;t really know the ABV now

Of course you can still get a gravity reading.
Either drop a hydrometer in the bucket or suck a sample out. That thin pellicle shouldn't affect the reading.

BTW, you cannot tell what organism is in there by just looking at a pellicle.

 

[Tall_Yotie]

Of course you can still get a gravity reading.
Either drop a hydrometer in the bucket or suck a sample out. That thin pellicle shouldn't affect the reading.

BTW, you cannot tell what organism is in there by just looking at a pellicle.

I thought lacto turned sugars into acid rather than alcohol. That's why I was staying I might not get an accurate value.

 

[IslandLizard]

I thought lacto turned sugars into acid rather than alcohol. That's why I was staying I might not get an accurate value.

Sure, acids have a different density than water, but at their relatively small percentage in beer, won't give that much change you'd notice on a hydrometer reading. Ask any Lambic (or other sour) brewer.

 

[jrgtr42]

Yes it seems so. Happens with on grain, at times desirable when making whiskey.

call me country bumpkin, or northern city boy, but is that sour mash?

 

[Dgallo]

There is probably a wild LAB in there but it’s been my experience they do not create any pellicle by themselves quickly if at all. But yes you certainly have an infection from a wild yeast/ bacteria. There’s also different acids created than just lactic acid from these organisms.

All that said, taste it. If it taste ok, let it ride until a stable fg. May be, the best beer you’ve ever made

 

[Gnomebrewer]

call me country bumpkin, or northern city boy, but is that sour mash?

Not quite. Sour mashing comes from using some of the leftover sour stuff (fermented beer or leftover wash after running a distillation) in the next batch.

 

[Tall_Yotie]

So how do distillers keep from getting infections from the grain if they don't boil thier wort before hand? I keep seeing recipes of dissolve sugar, but sugar water in bucket, top off with water, add grain. Seems like they'd always run a high risk.

 

[Dgallo]

So how do distillers keep from getting infections from the grain if they don't boil thier wort before hand? I keep seeing recipes of dissolve sugar, but sugar water in bucket, top off with water, add grain. Seems like they'd always run a high risk.

From my understanding they do it on purpose,that’s the whole sour mash. But again not boiling doesnt mean not pasteurizing their wort. At 150*f for 29 minutes will pasteurize the wort, though it was never boiled.