Rotten Egg smell on last days of ferment

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


Sep 1, 2010
Reaction score
Hi All,

Just made my first ever mead/s and got great results up until the last 1-2 days of the ferment when I detected rotten egg smell when I was doing my daily de-gass and punching the fruit cap down. Just wondering if you can correct my technique before my next mead please? I boiled a teaspoon of bread yeast and threw that in (with some extra pectic enzyme to break the fruit up some more) to feed the ferment and that seems to have stopped the creation of new gas, but waiting for the smell to leave fully before looking at splash racking which may risk further issues?

I will put my ingredients and methods below, but my questions are:

1. How do you calculate if you need extra nutrients for your fruit? I based it on the honey and water alone but with this large amount of fruit do I need to feed it more?
2. It got hotter the last few days, could this be the yeast stressed from the heat of 24 degrees C?
3. Is it normal for some to be produced at the very end? It was only a slight amount that needed your nose to the neck of the carboy to smell.
4. Can it be from racking away from the yeast colony and that meant it did not have access to the dead yeast as food?

I know it was only the last 1-2 days because it had been getting close to the airlock due to rising fruit so I was drinking a bit each day to test it out and lower the levels.

3.5kg Wildflower Honey
3 tea bags steeped for 10 minutes in 500ml boiling water to extract the tannin.
Water to bring up the level in fermentor to the 12 litre mark.
27 degrees C when pitched hydrated yeast into must.

Gravity reading of 1.098 to give a potential 12%ABV
Yeast Lalvin k1v-1116 (5 grams) is selected due to neutral results at 22 degree C fermenting temps
Hydrate the yeast in 50ml of 37 degree C water for 30 minutes, then add to must.

For Lalvin K1V-1116 and TOSNA 3, use 13.6 grams of 'Yeast Life O', in total split into 4 equal doses.
Added at 24, 48 & 72-hours after yeast pitch.
The last addition is added at the 1/3 sugar break

I used an iSpindle to track the brew up until the racking in on top of the fruit.

Fruit additions made in seconday when the ferment is slowing. Nothing done to the fruit to kill wild yeast besides 12% ABV, yeast is a killer type and the deep freezing.

One gallon (4L) got this fruit:
150g Raspberries
150g Blueberries
300g Strawberries

Another gallon got:
600g Blackberries
700g Loquats after being peeled and seeded.

Have 3 litres of traditional mead saved to top up the gallon carboys after fruit is removed to reduce head space or use as traditional mead.


  • mead.png
    85.3 KB · Views: 0
My thoughts.

1. Fruit addition dies not need additional nutrients. Fruit comes with some if its own. (Depending on the fruit.)
1a. Nutrient addition after about 9% alcohol will do little The yeast can not take advantage of it after about 9%. It also can add off flavors if not consumed.
2. Yes, heat does impact the yeast and could result in stress.
3. No, not normal. But does happen on occasion.
4. Racking would typically help not cause the issue.

Boiled bread yeast as a nutrient at this point wouldnt do anything for it.

The good news is it will age out. You can help it by degassing. I would not aerate or stir too vigorously. Stirring etc may casue oxidation. Best bet is to leave it with an airlock and let it degas over time. If you have a small vacuum pump that would accerate the process considerably.
Thanks for the reply and advice. So I will put it down to probably a 2 degree C increase in temp as I am not 100% sure what the temp was due to the ispindle not fitting inside the carboy and the fruit was really active fermenting. OK so I will follow the same method again and still rack away from the lees when adding fruit.

Boiled bread yeast as a nutrient at this point wouldnt do anything for it.
I figured it could not hurt as it would only add what a colony on the bottom would offer. The yeast life 0 nutrient really stinks (stale cat pee) and since it was over the 1/3 sugar break I was not going to add more of that.

If you have a small vacuum pump that would accerate the process considerably.
I do actually, its for bleeding car brakes with but I can probably make it work and this is a great idea thanks. I will rack it without splashing and then vacuum out the gases and leave the airlock on to bulk age it for a month or two before bottling.