Fermention problems: stuck? dead? Destined to fail

Discussion on brewing beer from malt extract, hops, and yeast.
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swheatbeer

Fermention problems: stuck? dead? Destined to fail

Post by swheatbeer » Fri Dec 09, 2016 11:01 am

Hi All,

I've had a fairly long break from brewing after selling me all grain kit.

I am easing my self back in to things with some recipe building using DME.

I came up with an idea to dissolve a DME bill to make a gallon of bitter hopped wort with OG at 1046. I have then split the batch into 8 mini 1litre buckets. While still hot I put in a different mix of aroma hops in each one. The idea is to rapidly decide on some funky new world hops for a 23l batch and then move back to all grain.

Once cooled I shake aggressively to dissolve some oxygen and pitch the yeast. This is where I think I have hit a wall.

I am using youngs ale yeast 6g satchets. I have been experimenting with pitching rates and my results are the same each time. Essentially I have 36hours of good fermentation and then it stops. Mostly the SG only drops 10-20 point leaving a bitter sweet part fermented wort.

At first I thought I was over pitching, using yeast 10-30times the normal amount. I figured that the high volume of cells consumed the oxygen and nutrients very quickly before it could eat all the sugar.

I tried a more scientific approach this week dosing the buckets with increasing rates from .2g (a touch higher than recommended rate) all the way to a full sachet in the last 600ml of wort. The higher pitched worts each has some yeast nutrients added to help the yeast along. .

Anyway. After 2 days they are all looking lifeless. I will give then another day and check the SG. No amount of aerating, heating up or shouting at them seems to help.

I know it's not really practical to be fermenting 600ml volumes but I can't fathom why they won't ferment out properly.

Everything is clean and sterile and the wort is fermented between 18-22celcius. Occasionally dropping to 17c.

can anyone help?

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Jocky
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Re: Fermention problems: stuck? dead? Destined to fail

Post by Jocky » Fri Dec 09, 2016 2:47 pm

Everything sounds right, from fermentation temperature to yeast volume.

My two best guesses otherwise would be that you've either got some duff DME (there has been stuff around in the past that doesn't ferment out right) or your hydrometer is broken (I presume that's what you're using?).
Ingredients: Water, Barley, Hops, Yeast, Seaweed, Blood, Sweat, The swim bladder of a sturgeon, My enemies tears, Scenes of mild peril, An otter's handbag and Riboflavin.

swheatbeer

Re: Fermention problems: stuck? dead? Destined to fail

Post by swheatbeer » Fri Dec 09, 2016 5:05 pm

Thanks Jocky,

I have used a couple of sources of different malt so happy it's not that.

I did wonder if the shop I got the yeast from might have stored it somewhere to hot and the yeast is in fact unhealthy. Like I said I get just over a day of good fermentation and then lifelessness.

Thinking about my process of splitting I might need to work out a way to more thoroughly aerate. Pouring 23l of wort into a standard fermenting bin creates quite a bit of default aeration and I think the 600ml mini batches miss that.

While I am shaking vigorously I think it may not be enough. When dividing up I am being very gentle to avoid spillage. Perhaps I need to fill up to 600ml from a great height (relatively speaking).

I think my hydrometer is fine but in any case the beer is too heavy and sweet for anywhere near full fermenting.

Cheers

Swheatbeer

Haydnexport
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Re: Fermention problems: stuck? dead? Destined to fail

Post by Haydnexport » Fri Dec 09, 2016 5:18 pm

are you sure you havent use the beer kit enhancer dried stuff instead of actual dme?

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Jocky
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Re: Fermention problems: stuck? dead? Destined to fail

Post by Jocky » Fri Dec 09, 2016 5:24 pm

What are you taking as 'activity'? Do you get a krausen on your wort? Are you waiting for it to drop back before measuring?

Technically dried yeast should have everything it needs to reproduce and thus doesn't need aeration. I do a little aeration with dried yeast in case, but it doesn't particularly worry me.

Another thought I had was the temperature swings might cause the yeast to stall out earlier than ideal. With small volumes the environmental temperature changes have more effect, and a sudden cooling could cause a stall.
Ingredients: Water, Barley, Hops, Yeast, Seaweed, Blood, Sweat, The swim bladder of a sturgeon, My enemies tears, Scenes of mild peril, An otter's handbag and Riboflavin.

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Jocky
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Re: Fermention problems: stuck? dead? Destined to fail

Post by Jocky » Fri Dec 09, 2016 5:24 pm

Haydnexport wrote:are you sure you havent use the beer kit enhancer dried stuff instead of actual dme?
Ooh, good point.
Ingredients: Water, Barley, Hops, Yeast, Seaweed, Blood, Sweat, The swim bladder of a sturgeon, My enemies tears, Scenes of mild peril, An otter's handbag and Riboflavin.

swheatbeer

Re: Fermention problems: stuck? dead? Destined to fail

Post by swheatbeer » Fri Dec 09, 2016 7:24 pm

Yeah, it's deffo DME but I am sure enhancer would still ferment further than 1046 down to 1030.

With regards to aeration. As I understand it all yeast will not work without Oxygen. Yeast consumes sugars and oxygen to produce CO2 and alcohols. Since boiling releases the dissolved oxygen then wort needs to have a degree of aeration post boil. For 23l batches a vigorous transfer is enough but I am not getting this with 600ml. I have seen people who do home brewing use aquarium aeration stones to ensure enough dissolved oxygen in wort.

I am gunna check SG tomorrow and likely have to chuck. I will then do a quick extract brew, say 1l and really aggressively introduce oxygen before pitching.

Temp swing could be an issue as the room is small with radiator and big window so it's possible it goes from 18-22/23 pretty rapidly and down again.

Cheers

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Jocky
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Re: Fermention problems: stuck? dead? Destined to fail

Post by Jocky » Fri Dec 09, 2016 8:16 pm

Oxygen at the beginning of fermentation is used in sterol production, allowing the yeast to reproduce. Oxygen is used up within 30 minutes.

Dry yeast is packaged with all the sterols they need to reproduce several times over.
Ingredients: Water, Barley, Hops, Yeast, Seaweed, Blood, Sweat, The swim bladder of a sturgeon, My enemies tears, Scenes of mild peril, An otter's handbag and Riboflavin.

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