Why does my beer smell like rotten eggs?

Who likes the smell of rotten eggs in their beer?

No one.

There was a time last year when I went to bottle my beer.

I'd just sterilized the bottles within an inch of their lives and I was ready to get the precious amber fluid into them.

And with that first pour from the fermenter into the green glass bottle, I got the most rank smell.

Rank.

Smell.

Of.

Rotten Eggs.

It was like I had cracked open a rotten egg and fanned it right up my nose!

It was disgusting like some kind of vile hydrogen sulfide bomb had been let off and the aroma was trying to burn my nostrils.



My brew was contaminated and I was gutted


There could have been a couple of reasons why the rotten eggy smell was happening. That rotten egg smell can usually be identified as the gas hydrogen sulfide.

It's probably the most obvious symptom that your beer has become contaminated.

It is the bi-product of the yeast strain or bacteria that have snuck into your brew (did we ever mention you've got to sanitize your equipment?).

The thing about lagers and rotten smells...

All is not necessarily lost, however.

You can fix this problem if the sulfide was produced by the yeast and not bad bacteria.

Lager yeast strains are quite prone to producing sulfide odours.

This is normal.

If you properly condition your bottled beer (the lagering process) by letting it stand for a few weeks, the smell should go away before it's time to drink.

This is why we also recommend that new brewers try an ale or two first to avoid this problem and being disappointed with their foray into brewing.

If you are worried about such smells, then over hopping your beer could help mask them but really, proper conditioning will work wonders. 

The news is not so good if you have a bacterial infection 

When is such news ever good?

In my case, I think it was clear that the beer was infected. The smell was pungent and a wee taste test suggested worse things were on offer.

But even though I was pretty sour, I was a stubborn bugger and bottled anyway on the off chance a bit of time conditioning would let everything sort itself out.

How wrong was I?!

The beer I tasted after two weeks was probably the worst thing I have ever put in my mouth and I once lost a beer drinking game involving a rinsed out kitchen cloth...

I reckon this bad beer would have made me sick if I had drunk a whole glass.

The rest of the brews were opened and tipped out. What was very interesting was there was a massive amount of CO2 / bubbles foam released when each cap was removed. They were giant gushers!

I imagine this was due to the unwanted bacteria continuing to work its own fermenting magic on the malt.

Either way, the lesson here as always is to do your absolute best to ensure that you have clean equipment and that you've done your best to sanitize it, and kept it clean during the beer brewing process.

If you find your beer in this condition before bottling, I'm afraid all you can do is dump the batch.

And then clean the heck of your fermenter and bottles!

This was a brewing lesson I will never forget. I'll be lax in some areas but will always make sure my equipment is clean and sanitized!

Skunked beer

While we're here talking about ruined beer, let's talk about skunked beer. This is when a chemical reaction happens in the bottled beer due to exposure to sunlight.

So named after the smell a skunk can release, lightstruck beer is caused by the UV radiation in light from the sun and retailer's lights. The so-alpha acids in the beer (which come from hops) are broken down and form a new compound in the beer by joining with any proteins floating around.

This compound stinks!

Brown glass is pretty handy at preventing this from occurring but not so much green bottles or clear glass. So, the trick to avoiding skunked beer is clearly to store your beer in the dark.

In summary:

• If you are brewing a lager, the smell could be 'normal' and may disappear after the beer has been conditioned
• It could well be your beer is contaminated by bacteria, in which case nothing will save it. Head to the pub for a self-pitying pint.
• Lightstruck or skunked beer can happen when the bottled beer is left in sunlight too long.
• Let your beer condition properly so that the yeast has time to work it's magic properly.

Leave a Comment bacteria, hydrogen sulfide, infection, problem solving, tricks and tips

From Off-Flavors to Contamination: How to Prevent Common Problems in Home Brewing

Home brewing can be a rewarding and fun hobby, but it is not without its challenges. From infections to off-flavors, there are many potential issues that can arise during the brewing process.

Understanding the science behind these problems and taking preventative measures and avoiding mistakes can help you produce great-tasting beer every brew day.

In this list, we will cover 25 things that can go wrong during home brewing, including the problem, its causes, and potential remedies.

1. Infections: Infections can occur when bacteria or wild yeast contaminate the wort or beer. This can be caused by using improperly sanitized equipment or not properly cleaning equipment between batches. To prevent infections, use proper sanitation practices and clean equipment thoroughly between batches.
2. Oxidation: Oxidation occurs when beer is exposed to too much oxygen, causing it to taste stale or cardboard-like. This can be caused by improper bottling techniques or using equipment that is not airtight. To prevent oxidation, use proper bottling techniques and ensure all equipment is airtight.
3. Chlorophenols: Chlorophenols can cause beer to taste like band-aids or medicine. They are often caused by using chlorine-based sanitizers or using tap water that contains chlorine. To prevent chlorophenols, use non-chlorine-based sanitizers and consider using filtered or distilled water.
4. Diacetyl: Diacetyl is a buttery or butterscotch-like flavor that can be caused by bacterial contamination or a yeast strain that produces high levels of diacetyl. To prevent diacetyl, use appropriate yeast strains and ensure equipment is properly sanitized.
5. Acetaldehyde: Acetaldehyde can cause beer to taste like green apples or freshly cut pumpkins. It is often caused by not allowing the beer to properly ferment or by using an inappropriate yeast strain.
6. Esters: Esters can cause beer to taste fruity or like banana. They are often caused by using an inappropriate yeast strain or by fermenting at too high of a temperature. To prevent esters and monitor fermentation temperature.
7. Fusel alcohols: Fusel alcohols can cause beer to taste harsh or solvent-like. They are often caused by fermenting at too high of a temperature or by using an inappropriate yeast strain. To prevent fusel alcohols, monitor fermentation temperature and use appropriate yeast strains.
8. Metallic off-flavors: Metallic off-flavors can cause beer to taste like metal or pennies. They are often caused by using equipment that is not properly cleaned or by using metal equipment that is not stainless steel. To prevent metallic off-flavors, properly clean and sanitize all equipment and use stainless steel equipment.
9. Phenols: Phenols can cause beer to taste like band-aids or smoke. They are often caused by bacterial contamination or using an inappropriate yeast strain. To prevent phenols, ensure equipment is properly sanitized.
10. Skunked beer: Skunked beer has a distinct skunky odor and taste, similar to that of a skunk. It is often caused by exposing beer to light, especially UV light. To prevent skunked beer, store beer in a dark place and avoid exposing it to light.
11. Too sweet: Beer that is too sweet can be caused by using too much unfermentable sugar or by not allowing the beer to properly ferment. To prevent beer from being too sweet, use appropriate amounts of fermentable sugar and ensure the beer is fully fermented.
12. Vegetal off-flavors: Vegetal off-flavors can cause beer to taste like cooked vegetables or grass. They are often caused by using an inappropriate amount or type of hops, or by not properly storing hops. To prevent vegetal off-flavors, use appropriate amounts and types of hops and store them properly in a cool, dry place.
13. Haze: Haze in beer can be caused by a variety of factors, including using improper ingredients, not allowing the beer to fully ferment, or not properly clarifying the beer before bottling. To prevent haze, use appropriate ingredients, allow the beer to fully ferment, and clarify the beer before bottling.
14. Low carbonation: Beer that is low in carbonation can be caused by not adding enough priming sugar or by not properly carbonating the beer before bottling. To prevent low carbonation, ensure the proper amount of priming sugar is added and properly carbonate the beer before bottling.
15. High carbonation: Beer that is over-carbonated can be caused by adding too much priming sugar or by over-carbonating the beer before bottling. To prevent high carbonation, use the proper amount of priming sugar and properly carbonate the beer before bottling.
16. Gushing beer: Gushing beer occurs when the beer over-foams and spills out of the bottle. This can be caused by over-carbonation or bacterial contamination. To prevent gushing beer, properly carbonate the beer and ensure equipment is properly sanitized.
17. Sour beer: Sour beer can be caused by bacterial contamination or by using an inappropriate yeast strain. To prevent sour beer, ensure equipment is properly sanitized and use appropriate yeast strains.
18. Cloudy beer: Cloudy beer can be caused by a variety of factors, including using improper ingredients, not allowing the beer to fully ferment, or not properly clarifying the beer before bottling. To prevent cloudy beer, use appropriate ingredients, allow the beer to fully ferment, and clarify the beer before bottling.
19. Bitter beer: Beer that is too bitter can be caused by using too many bittering hops or by allowing the beer to ferment too long. To prevent beer from being too bitter, use appropriate amounts of bittering hops and monitor fermentation time.
20. Weak beer: Beer that is too weak can be caused by using too little malt or not allowing the beer to fully ferment. To prevent weak beer, use appropriate amounts of malt and ensure the beer is fully fermented.
21. Hot alcohol flavors: Hot alcohol flavors can cause beer to taste boozy or like rubbing alcohol. They are often caused by using an inappropriate yeast strain or by fermenting at too high of a temperature. To prevent hot alcohol flavors you need to regulate fermentation temperature.
22. Contamination from wild yeast: Contamination from wild yeast can cause beer to taste sour or funky. It is often caused by using equipment that is not properly sanitized or by not properly cleaning equipment between batches. To prevent contamination from wild yeast, use proper sanitation practices and clean equipment thoroughly between batches.
23. Inconsistent carbonation: Inconsistent carbonation can occur when different bottles of beer have different levels of carbonation. This can be caused by uneven distribution of priming sugar or uneven carbonation. To prevent inconsistent carbonation, ensure even distribution of priming sugar and properly carbonate the beer before bottling.
24. Inconsistent flavor: Inconsistent flavor can occur when different bottles of beer have different flavors. This can be caused by uneven fermentation or uneven bottling practices. To prevent inconsistent flavor, ensure even fermentation and bottling practices.
25. Cider-like flavors: Cider-like flavors can cause beer to taste like apple cider or vinegar. They are often caused by bacterial contamination or by using an inappropriate yeast strain. To prevent cider-like flavors, ensure equipment is properly sanitized and use appropriate yeast strains.

In conclusion, there are many potential problems that can arise when home brewing beer.

These problems can range from off-flavors to contamination and can be caused by a variety of factors such as improper ingredients, poor sanitation, and incorrect fermentation times. While these issues can be frustrating, they are a normal part of the home brewing process, and even the most experienced brewers will encounter them from time to time.

However, the best brewers take these challenges in stride and learn from their experiences.

By properly preparing equipment, using appropriate ingredients, and maintaining proper sanitation practices, home brewers can minimize the risk of encountering these problems and create delicious, high-quality beer.

With a lil bit of patience and practice, any home brewer can become a master of their craft and create beer that is both delicious and satisfying.

Leave a Comment acetaldehyde, isoamyl acetate, problem solving

⇒ How do I tell if my beer fermented properly? (I really want to drink it)

How to tell if my beer brew has fermented?

Fermentation is the name of the game when making beer.

If you don't have fermentation taking place, you simply don't have beer.

You have just have a 23 liter bucket of watery malt.

Homebrewers can face fermentation stage issues and a common problem is that fermentation has not begun. A typical sign is that there are no bubbles coming through the airlock.

But is no bubbles in the airlock really a sign of a lack of fermentation?

The first thing to bear in mind is that it can take at least 15 hours of your Earth time before the CO2 bubbles start gurgling through the airlock. 

So don't go drowning your sorrows just yet if the bubbles haven't started. If you think that your beer hasn't started brewing there's some problem-solving you can do. 

If you are using a glass fermenter you can look for a dark scum that rings around the water level mark. You can probably see it through the standard white fermenter drum as well.

Or check for signs of foam or the krausen as it is affectionately known. Give it 20 - 48 hours before you start to worry.

If using a plastic drum you might be able to see through to check for the scum. Another trick is to take out the airlock and try and peek through the whole to identify scum or foam.

Also, did you firmly seal your fermenter? If not, the CO2 is possibly passing out via the lid and not the airlock meaning the pressure build-up is not sufficient for gas to pass out the water trap.

We're going to assume your fermenter is in a warm place and not in some shed where the temperatures are approaching zero degrees centigrade. Your yeast will go to sleep if this is the case.

You could also check the gravity by using a hydrometer.

I'll assume you know how to use one.  The beer has usually finished fermenting if the final gravity reading is  1/3 to 1/4 of the original gravity. This, of course, means you took an original reading when you first prepared your beer.

You did do that right?

If you have the same reading 24 hours apart - that's your final reading and an indication that the fermentation is finished. 

Don't bottle your beer just yet, let it mellow for a bit longer.

The longer the better your brew will probably be. If you are a beginner brewer, trust me on this. Let you brew rest up just a little bit longer than you may have the patience for.

Brewing is a game of patience, and those who wait are rewarded with good-tasting, clear beer. 

So why weren't there any bubbles in the airlock? 

That's a fair question to ask.

It could be that there was a leak that allows the CO2 to escape (to teach you to suck rotten eggs, those bubbles in the airlock are carbon dioxide gas, the by-product of fermentation).

You may have not tightened the drum enough or possible not screwed in the tap properly.

It's a good idea to check this is the case before you worry too much.

• If you didn't see any signs of fermentation it could be that it's too cold to brew.
• Is your batch of beer in a warm enough place?
• If you're brewing during summer months, it's probably not too cold.

If you've left your beer in a cold place in the shed, then it may be too cold. If it's too cold to brew in your 'man shed' - say it's the middle of winter, you might want to bring your brew inside the house.

You could consider wrapping it in blankets or old sheets (I do this all the time just because that's what I learned to do at University in the cold, windy town of Palmerston North, NZ. This is a handy trick and will help to keep the chill off your beer. I think this trick works best if the beer is already warm enough to brew. 

Maybe leave it in the laundry if it's a warm place?

When I brew in winter I will often leave the fermenter our the warm kitchen or living room at least overnight so that the fermentation process has a decent chance to start. My wife hates that but still drinks the beer so go figure. 

Some brewers like to use heat pads (try the Mangogrove Jacks one) or panels to keep the beer at a consistently warm temperature. If you do wish to use a pad, you'll need to be able to store your brew close to a power socket so the heat pad can operate.

Yeast issues?

Another more serious reason for beer failing to ferment is yeast failure.

This may occur if the yeast has become dry. This is why you will hear a constant refrain from expert beer users to only use fresh ingredients.

In the case of a beer kit brewer, this means do not purchase old stock as the yeast could be too old (I do suspect however this is a bit of a housewives tale - as stock should rotate fairly regularly). 

However, in our experience, we haven't had this problem with a beer kit yet. 

A key trick is to add (pitch) the yeast at the appropriate temperature - if using a beer kit you will be well off to generally follow the temp instructions - you especially do not want to add the yeast if the solution is too cold as it may be hard for the yeast to get traction - and whatever you do, don't add yeast to boiling water (if that's what you are using to mix everything together) - as that will almost certainly kill the yeast and ruin any chance of your beer successfully fermenting.

So in summary here are some problem-solving tips:

• Check for leaks that allow the CO2 to escape - tighten the fermenter drum
• Look for foamy residue - if you see it, you're OK
• Look for scum residue - if you see it, you're OK
• Make sure the temperature is appropriate for the kind of beer you are making
• Consider using a heat pad to ensure a consistent brewing temperature

Image credit to Quinn Dombrowski via Creative Commons Licence

1 comment beer kit, fermentation, problem solving

The truth about contaminated homebrew beer

It only takes one bad batch of contaminated beer for beer enthusiasts to be converted to the mantra of 'sterilization is mandatory'.

And that's the best approach you can have when brewing beer.

Keeping your equipment and preparation space clean and sanitary will keep you on course for a fine tasting brew.

Things do go wrong.

You might accidentally drop something into your batch.

Maybe your three-year-old son thought he was helping Dad out by throwing the air lock into it (yes, that actually happened).

Maybe you found a Weta at the bottom of your bottle? (true story)!

Maybe you managed to drop some bottle caps or a stirring spoon into it and then let it ferment:

I found the missing spoon!

Or maybe some bacteria decided to live in your fermenting drum. 

Does this mean you've contaminated and ruined your batch?


The short answer is no, yes and maybe.

But the chances are that you haven't screwed things up.

If you've done diligent preparation so that everything else is clean, then the chances are that dropping the odd utensil into your batch is not going to ruin it.

On a couple of occasions, I have been pushing the airlock into the hole in the top of the fermenter lid. As I have done this, I managed to push the rubber bung through the hole and into the batch.

Quelle Horreur! 

I was left with no choice each time to grab a large metal spoon from the kitchen drawer to try and fish the bung out. I had no time to sterilize the spoon - I'd pitched the yeast already and wanted to lock that drum down tight.

Did I ruin my beer by exposing it to a rubber bung and an unsanitized spoon? I possibly could have but in the end, my brews turned out absolutely fine.

Here's my reason why this scenario worked out OK.

If you make sure that you have already produced a hospitable environment for your yeast to take charge of your brew, it's like any introduction of foreign micro-organisms will not be calamitous.

The yeast you use is beer yeast. It's been cultivated for many years to brew the best kind of beers and it knows how to do its job.

If it's just a minor contamination by way of a spoon or dropped airlock (chances are they were actually quite clean as opposed to say a Matchbox toy car) it's more than likely your yeast will win the tussle for beer fermenting supremacy.

I think it's fair to say that a small mistake is not fatal to your beer

A large mistake such as not preparing your fermenter properly (cleaning and sanitizing) would probably have dire results.

If your beer is actually contaminated (smells of rotten eggs, a taste test reveals a disgusting taste) then you may have to consider dumping your brew.

Update: Believe it or not, shortly after writing this post, I managed to find this in my fermenter. The beer was fine.

Image credit to ellai via Creative Commons Licence. We have no idea if Ellai prefers Star Wars quotes, Star Trek or has even read the Mortal Engines book. Have you?

1 comment air lock, bacteria, beer brewing, contamination, problem solving, sterilisation