There might have been some infection in the preparation, although we cleaned everything carefully.
Clean first, sanitize next. All need to be done thoroughly and dexterously with everything that touches your chilled wort, or beer.
Pay attention to nooks and crannies such as occur in certain lids, and the groove.
What kind of cleaner(s) and sanitizer did you use?
Lifting the lid during fermentation is often discouraged. And when you must, make sure to clean and sanitize it first, especially around the groove area, and again when replacing it.
Large headspaces are comfy for krausen to prevent blow off, but become an issue when conditioning beer for longer times. More so after the lid has been lifted, as all the CO2 in the headspace is lost and replaced by air (containing 21% Oxygen).
As this was our first ever brew, we also made the mistake of adding sugar when launching the fermentation, that might have even accelerated it further.
Sugar should not cause infections, except in extreme cases where it may contain bacteria, mold, and such. Therefore it's often advised to add the sugar to the boil or boil the sugar with some water making a syrup that get added to the fermenter later on, when fermentation starts to slow.
As for “secondary” fermenter, not voluntary, but indeed Brussels is known for having some specific “ferments” flying around in the atmosphere - giving us the Lambic
That could be an issue, sure! Although you could use that to your advantage when brewing mixed fermentation sours.
Generally, we try to aim for short lag times by pitching a good amount of healthy yeast, that takes off fast, so it can get well ahead of any stray organisms floating in the midnight air.
What I was referring to was using secondary fermenting vessels, which appear in old and often outdated brewing instructions. The benefit of secondaries has been debunked mostly over the past 10-15 years, except in some cases, none in the beginners brewing realm.
You're gonna try again, yes?
