This is my first time posting to this forum, so if I make some edict mistakes I apologize in advance.

I have brewed this recipe, https://www.homebrewersassociation.org/homebrew-recipe/beer-recipe-of-the-week-crabapple-lambicky-ale/, for the second time and this time there are white splotches coming up on top.

I am fairly certain this is contamination but I am not sure what I should do. My instinct is to bottle it now and see what it tastes like when it is carbonated.

This is only my second contamination so I do not have a lot of experience with this. Any advice is appreciated.

Update: The beer that I brewed did have a sour pitch added, https://torontobrewing.ca/products/lallemand-wildbrew-sour-pitch-10-g. It is a lactobacillus plantarum bacteria and looking online a lactobacillus contamination can look like what I'm seeing. I'm concerned though cause I do not remember seeing it last year and I am wondering if I should bottle it early.

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  • 1
    Looks either like normal bubbles, or the start of a lacto culture to me- which is what you pitched. I'd continue either way and taste before bottling. Don't resort to dumping out until you know it's lost!
    – rob
    Commented Apr 6, 2021 at 12:22

2 Answers 2


RDWHAHB. My bet would be that it's your lacto culture waving it's flag. Technically, it is contamination, but one that you want for lambic. My last lambic had similar 'bug islands' and was really good. I think you're OK.


Looks a little like the beginning of this: https://www.brew-dudes.com/infected-beer/597

If it were me, I'd probably go with a taste test to figure out what to do next.

Not sure how long you've been brewing (and apologies if this adds insult to injury, not my intent) but contamination is rare from what I understand. You may want to take a close look at how you are cleaning/sanitizing. Depending on the frequency of this contamination, you might have a crevice somewhere in your equipment where stuff is not getting cleaned up.

  • I think that you might be on to something with that post. My splotches do look similar. This beer did use a sour pitch that contains lactobacillus plantarum and it looks like a lactobacillus infection after some more research online. I don't remember it looking like this so late in the process last year though. I have updated my question with the sour pitch used Commented Apr 5, 2021 at 16:07
  • Also, this is only my second infection and I have brewed somewhere around 20 ish beers. One was infected because I was not using warm enough water when sanitizing (it was a simple pilsner). Given that this beer was somewhat high risk since I added chopped crabapples which were only sanitized by freezing I don't think my equipment is the problem. If it happens more often I'll have to look into that though Commented Apr 5, 2021 at 16:11
  • Not sure what you mean by 'warm enough water' but I think you're talking about pasteurizing. Yeah that gets a little tricky. Needs to be hot enough, for long enough, to kill off bacteria without destroying whatever adjunct you are adding. Google seems to be all over the map for temp and time. I use 165F for 10 mins in the microwave to pasteurize my cider additions or starters for yeast. Seems to have worked OK so far. Good luck!
    – HomeBrew
    Commented Apr 8, 2021 at 11:15
  • @KodyRogers just curious. How did this beer end up? Sometimes they end up coming out OK even with strange things growing on top.
    – HomeBrew
    Commented Oct 16, 2021 at 11:40
  • It actually turned out good. It tastes about the same as the last time I did it, so it is my guess the same infection occurred and I just forgot. I am starting to get better at logging different things while brewing so hopefully, I'll know what to anticipate better. Commented Dec 13, 2021 at 0:40

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