Brewing beer is fun. Waiting for it to be done fermenting or bottle condition, not so much… The worst is when you think you have waited long enough, crack open a cold one and listen to the nice hiss, pour a tall glass, look at the bubbles crash against the nice foam on top, and after a few minutes of contemplation you go to take a swig…
Yuck!
You spit out the green-apple sour tasting beer and feel like pouring it down the drain…
Whoever said it’s hard to screw up beer needs to try this one… oh wait, they’ll say you just have to leave it conditioning longer. Time heals all wounds…
Who cares anyways, all we care about is how to fix it…
Unfortunately, this is one of those flavors that only gets worse with time… The most common cause of green apple taste in beer is incomplete fermentation…
Usually something done by new impatient brewers who read too many forums and fill themselves with conflicting information on racking their beer to a secondary fermenter not really knowing why they would do such a thing…
All they read is that the secondary fermenter will clean up the beer and will many times rack their beer before fermentation is complete.
Others will simply bottle after a week or so… sometimes because that’s just what the instructions say…
Whatever the case, the point is, yeast turns sugar into alcohol, but before it fully converts sugar into alcohol it turns sugar into a green apple tasting compound known as Acetaldehyde.
Incomplete fermentation is just that, the yeast have turned sugar into acetaldehyde and not alcohol which can give you all kinds of flavors, not just green apples…
Let’s see, on the menu we have:
Green apples
Cut grass or green leaves
Pumpkin
And today’s special, latex paint…
Not exactly the flavors that go well with beer. Although some brewers have attempted to brew pumpkin flavored beer… I’m still not into the whole adding fruit flavors to beer… it just doesn’t sound good…
Now let’s say you are special… not ride the short bus special, but you’ve run into a special situation where you did leave your beer fermenting for a good 4 weeks… perhaps even roused the yeast by swishing the fermenting bucket around and got a good Final Gravity reading?
And you still got green apple tasting beer…
Well, your case may be that of oxidation… most likely coming from hot side aeration, meaning you exposed your wort to oxygen before cooling it below 80 F… or the second most common cause (especially if it’s getting worse with time) could be that you didn’t bottle your beers all the way to the top and left too much oxygen in your bottles.
Leaving too much oxygen in bottles is not the cause alone, it is usually accompanied by poor sanitation practices… and what good people consider good sanitation practices are often times not good sanitation practices…
Point is, oxidation can sometimes reverse ethanol into acetaldehyde giving you the green apple taste… you know if oxidation is the cause if it has a sherry like flavor, which is a type of vinager flavor… kinda cidery and not so taste, unless you are into vinager flavored salads…
Anyways, I know this because the second batch I brewed came out with this flavor and those were the causes, so learn from my mistakes and don’t make them yourself… over and out…
