Fermentation Issues

[Lillywhite]

Hi,

New to the site but have been brewering for about 9 years, I just started brewing AG about 3 years ago and then stopped brewing for personal reasons for about a year and a half.

I am now back in it and am not having the success I use to even though I have improved my system and processes, I have brewed 3 brews since returning, the first was a complete failure resulting in infection and tipping on the garden. I am seeking assistance or advice with my last 2 brews.

The issue I am having is the wort is not fermenting out, the first (of the last 2) final SG reading was 1.019 (checked over consecutive days). The last brew (which is still in secondary) is only down to 1.028, I'll talk you through the last brew:

Brew Date: 21/11/10
Style: Germ Pils
Yeast: Saflager 34/70 11.5g
Vol: 22L
OSG: 1.058
Pitching Temp: 24C (approx 1030 that night)
Wort Temp: 13C (The next morning) Airlock bubbling away

01/12/10
Temp: 13C
SG: 1.028 Airlock bubbling slowed down so transferred to secondary.

07/12/10
Temp: 13C
SG: 1.028

09/12/10
Temp: 13C
SG: 1.028

Secondary Airlock did commence bubbling but only for 24 - 48 hours. I still have the beer in secondary.

The wort taste and smell ok, will still keg it and drink it but would really like to work out what is going wrong.

Issues I know I need to fix but don't believe this to be the reason for the above results.

- My current immersion chiller only gets the wort down to 35C, I then moved the fermenter to the fridge and left it as long as I could (couple hours) as concerned about infection if I leave it to long. I am improving my wort chilling before the next brew, currently use copper coil in kettle with garden hose buried in ice in esky, am going to get second copper coil that will go in esky with ice, this should keep the chilling water colder longer increasing speed at which wort cools and should also cool wort closer to pitching temp.

The reason I don't believe this to be the problem is because I did it this way previously and it still fermented out.

I have scanned previous threads to see if anyone else has posted this problem to no avail, so if you have gone through this or have any advice it will be much appreciated.

Cheers,

Sean

 

[DJR]

Checked your thermometer for accuracy? If the mash temp is too high and your thermometer tells you otherwise then that could be the problem with high FG

 

[ekul]

What are you using to measure your gravity? ie hydrometer or refractometer? If its refractometer the readings won't be accurate for fermented wort as you need to do adjustments to get an accurate reading. (the alcohol makes it not work)

 

[[email protected]]

Sounds like mashing temp to me. Have a read through this.

http://www.howtobrew.com/section3/chapter14.html

 

[argon]

First thing that jumps to mind is wort aeration and yeast handling.

How are you doing both? Once cooled are you aerating the wort prior to pitching?

How are your pitching? Appropriate pitching rates? Active starter? Are you rehydrating your dry yeast?

 

[Lillywhite]

What are you using to measure your gravity? ie hydrometer or refractometer? If its refractometer the readings won't be accurate for fermented wort as you need to do adjustments to get an accurate reading. (the alcohol makes it not work)

Hydrometer

 

[Lillywhite]

First thing that jumps to mind is wort aeration and yeast handling.

How are you doing both? Once cooled are you aerating the wort prior to pitching?

How are your pitching? Appropriate pitching rates? Active starter? Are you rehydrating your dry yeast?

Good point Argon, something I didn't consider was aeration of wort. My previous brewing experiences involved pitching yeast immediately after transfering wort to fermenter not leaving it sit for a couple hours. If I get my immersion chiller sorted so wort transfer occurs at pitching temp this point should be rectified or get an aeration stone. I didn't rehydrate my yeast as I have had limited success with this previously (just did the 'sprinkle over the top and stir in'), may need to work on this also.

One of the reasons I love brewing AG is the learning process, so much more to consider than chucking a can into a couple litres of hot water with some dextrose.

Have the ingredients for my next brew, will work on the points you have provided this weekend.

Cheers,

Sean

 

[WarmBeer]

Checked your thermometer for accuracy? If the mash temp is too high and your thermometer tells you otherwise then that could be the problem with high FG

I have first hand experience with the issue DJR mentioned.

When I moved to All Grain, my second and consecutive couple of beers were far too cloying and under attenuated. I did a calibration of my thermometer in boiling water, and found it was about 5 degrees out. Turns out when I was mashing at 67 degrees, I was really mashing at 72. Turns out there was an air pocket in my thermometer that was skewing the reading.

Your best bet is do a full calibration exercise, first in an ice-slurry bath, then in active boiling water. This will give you a fair degree of confidence that your thermometer is reading correctly (enough).

 

[kevin_smevin]

Howdy.

Could be your mashing temp or could be your yeast. There is a test called apparent attenuation limit (AAL) test which should tell you whats what. Basically, next time you do a brew, take about 1-2L of your wort and put it in a sanitised flask or botttle and add about 1tsp of dried yeast. Use something reliable like safale US05. Put this bottle in a warm spot - warmer then you would usually ferement. Your basically doing a forced ferment to see how fermentable your wort is. If you find that your AAL test gives a significantly lower FG then your actually brew, your problem lies in your yeast handling - not pitching enough, not aerating enough or something like that. If your AAL test gives you a similar final gravity, your problem most likely lies in your mash temp being to high, leaving your wort with too many unfermentable sugars. This is a good test to do routinely if you can feel assed as it provides some good feedback on your process. You should always use the same yeast in your AAL - it does not have to be the same yeast your using in your proper ferment. Its best to use a reliable yeast that is cheap and fairly well standardised - hence the dried yeast. Different yeast have different attenuation limits, ie they have different abilities to ferment wort. The differences are not huge though and you will start to figure out what to expect - you might expect US05 to consistently ferment out 2 points lower then you bohemiam pills yeast for example - if that happens every brew you know your on the right track.

The other thing to do to reach your terminal gravity is to raise the temp a couple of degrees towards the end of ferment. In this case though you probably thought it still have a good 10-15 points left to ferment out so wasn't much help here.

Good luck

 

[argon]

Good point Argon, something I didn't consider was aeration of wort. My previous brewing experiences involved pitching yeast immediately after transfering wort to fermenter not leaving it sit for a couple hours. If I get my immersion chiller sorted so wort transfer occurs at pitching temp this point should be rectified or get an aeration stone. I didn't rehydrate my yeast as I have had limited success with this previously (just did the 'sprinkle over the top and stir in'), may need to work on this also.

One of the reasons I love brewing AG is the learning process, so much more to consider than chucking a can into a couple litres of hot water with some dextrose.

Have the ingredients for my next brew, will work on the points you have provided this weekend.

Cheers,

Sean

If you can get your chiller to spit out the wort at pitching temps that would go a way to solving the problem. Just get one of these for when you transfer to fermenter to add heaps of air to the cool wort.

As for sprinkling the yeast on the surface. Recently there has been discussion that around 50% of the cells from a dry packet will die if pitched directly to the surface. If i remember correctly that's direct from the manufacturers. Best bet is to rehydrate in a cup of 25C pre boiled water and let it hydrate prior to pitching to a well aerated wort. This should get the yeast up an fermenting in no time.

 

[felten]

If it's not a measurement issue then my money is also on yeast. The pitching rate calc says you need 23g of 100% viability dried yeast with your beers specs. Lets say your yeast pack was 100% viability for arguments sake, you've only used half that @ 11.5g; and if you aren't properly re-hydrating, like argon said, you could be killing off another half of that altogether.

 

[Jerry]

Sean,

Have you checked the accuracy of your hydrometer?

Also re the 'correct' way to pitch dry yeast;-

-I've rehydrated,
-sprinkled on surface and left alone,
-sprinkled on surface and stirred in,

and done all of these things with and without aerating and I've never seen any real noticable difference between them all.

Maybe post up the recipe details to see if there are any hints in the ingredients you're using.

Cheers

Scott

 

[Lillywhite]

If it's not a measurement issue then my money is also on yeast. The pitching rate calc says you need 23g of 100% viability dried yeast with your beers specs. Lets say your yeast pack was 100% viability for arguments sake, you've only used half that @ 11.5g; and if you aren't properly re-hydrating, like argon said, you could be killing off another half of that altogether.

Thanks for that, one question though, when brewing an extract kit brew of the same volume and similiar SG, why is it the little 7g (if my memory serves correct) packet of yeast was sufficient yet now I need 23g? even the 11.5g yeast package states sufficient for 20 - 30 litres. Not questioning anyones knowledge just trying to get the facts as I did play with a calculator that said I needed 23 odd grams of yeast but just thought I put the information in wrong or something.

Thanks to everyone for the advice, three things I will do with my brew this weekend: 1. Use 23g of yeast. 2. Rehydrate the yeast and 3. Improve my wort chiller and I will probably do those checks on my equipment as well.

Someone also asked what my recipe was:

4200g German Pils
500g Munich
250g CaraHell
60g Saaz 60 min
25g Tett 15 min
20g Tett 3 min
Saflager 34/70

Cheers,

Sean

 

[np1962]

Thanks for that, one question though, when brewing an extract kit brew of the same volume and similiar SG, why is it the little 7g (if my memory serves correct) packet of yeast was sufficient yet now I need 23g? even the 11.5g yeast package states sufficient for 20 - 30 litres. Not questioning anyones knowledge just trying to get the facts as I did play with a calculator that said I needed 23 odd grams of yeast but just thought I put the information in wrong or something.

Thanks to everyone for the advice, three things I will do with my brew this weekend: 1. Use 23g of yeast. 2. Rehydrate the yeast and 3. Improve my wort chiller and I will probably do those checks on my equipment as well.

Someone also asked what my recipe was:

4200g German Pils
500g Munich
250g CaraHell
60g Saaz 60 min
25g Tett 15 min
20g Tett 3 min
Saflager 34/70

Cheers,

Sean

As far as your yeast question goes I'll give a quick answer as far as my knowledge goes.
When you pitch your yeast the first thing they do is build up the numbers to a stage where they are in sufficient amounts to be able to attack the sugars in your wort and produce alcohol.
To do this they use the oxygen in the wort, the more times they need to multiply to get to the fermenting stage then the more oxygen/ energy they use. The more times they bud the more stress on the yeast and the more likely it is to give up early.
With K&K there is a lot of simple sugars that require less yeast numbers/ energy to ferment, as you progress through extract and onto AG you are producing progressively more complex sugars in the wort and the yeast need to work harder and in greater numbers than before hence a higher pitching rate is required.
You are also using a lager yeast at lower temperatures so will need a higher pitch rate again.
Aerate your wort well with either pure oxygen injection for about 30 seconds, airstone for 5minutes minimum or just giving your fermenter a really good shake for as long as you have the energy, 5-10 mins will be good enough. then use a pitch rate calculator to estimate the amount of yeast to pitch.

I think this is most likely to be your main issue, I can't see a slightly high mash temp being the problem as the FG is just so much out of the expected range. You would need to be mashing well into the 70's and denaturing the enzymes for it to make such a difference.

Cheers
Nige

 

[Jerry]

Thanks for that, one question though, when brewing an extract kit brew of the same volume and similiar SG, why is it the little 7g (if my memory serves correct) packet of yeast was sufficient yet now I need 23g? even the 11.5g yeast package states sufficient for 20 - 30 litres. Not questioning anyones knowledge just trying to get the facts as I did play with a calculator that said I needed 23 odd grams of yeast but just thought I put the information in wrong or something.

Sean,

Some people recommend / prefer to use 2 packets (ie. 23g) when making a lager.

Thanks for posting the recipe.

I haven't calculated it but your OG of 1.058 seems a little high for 5 kg of grain at, I'm assuming, around 22-23ltrs?

Definately worth checking your hydrometer.

Scott

 

[itguy1953]

With a K&K you add cold water from the tap. This water has oxygen in it, and even more if you have an aeration nozzle on your tap.

Boiled water has no oxygen in it as the boiling drives off the oxygen.

1 packet of lager yeast will ferment the wort, it will just stop short leaving the beer a little sweet.

Cheers

Thanks for that, one question though, when brewing an extract kit brew of the same volume and similiar SG, why is it the little 7g (if my memory serves correct) packet of yeast was sufficient yet now I need 23g? even the 11.5g yeast package states sufficient for 20 - 30 litres. Not questioning anyones knowledge just trying to get the facts as I did play with a calculator that said I needed 23 odd grams of yeast but just thought I put the information in wrong or something.

Thanks to everyone for the advice, three things I will do with my brew this weekend: 1. Use 23g of yeast. 2. Rehydrate the yeast and 3. Improve my wort chiller and I will probably do those checks on my equipment as well.

Someone also asked what my recipe was:

4200g German Pils
500g Munich
250g CaraHell
60g Saaz 60 min
25g Tett 15 min
20g Tett 3 min
Saflager 34/70

Cheers,

Sean

 

[Bretto77]

Thanks for that, one question though, when brewing an extract kit brew of the same volume and similiar SG, why is it the little 7g (if my memory serves correct) packet of yeast was sufficient yet now I need 23g? even the 11.5g yeast package states sufficient for 20 - 30 litres. Not questioning anyones knowledge just trying to get the facts as I did play with a calculator that said I needed 23 odd grams of yeast but just thought I put the information in wrong or something.

Thanks to everyone for the advice, three things I will do with my brew this weekend: 1. Use 23g of yeast. 2. Rehydrate the yeast and 3. Improve my wort chiller and I will probably do those checks on my equipment as well.

Someone also asked what my recipe was:

4200g German Pils
500g Munich
250g CaraHell
60g Saaz 60 min
25g Tett 15 min
20g Tett 3 min
Saflager 34/70

Cheers,

Sean

Sean,
I would agree with the other guys on the forum. When brewing a lager you need about double the number of cells as they need to do the job at a lower temp. I recently did a Munich Helles with s-23 lager yeast pitched two packets of re-hydrated yeast. I have been experiementing with yeast starter and repitching off a previous batch just did three batches all using US-05 using one packet. The fermentation was so strong that it was done in 3 days at 18c. I'm convinced that re-pitching yeast provided you practice good sanitation, is the best way to go. Only worry I have is the possibility of over pitching.

I'm pretty local to you mate, I'm in Boonah. Would be great to catch up and chat. There are a few guys around the region on this formum from Kalbar & Aratula.

Cheers
Bretto

 

[Lillywhite]

Hi,

New to the site but have been brewering for about 9 years, I just started brewing AG about 3 years ago and then stopped brewing for personal reasons for about a year and a half.

I am now back in it and am not having the success I use to even though I have improved my system and processes, I have brewed 3 brews since returning, the first was a complete failure resulting in infection and tipping on the garden. I am seeking assistance or advice with my last 2 brews.

The issue I am having is the wort is not fermenting out, the first (of the last 2) final SG reading was 1.019 (checked over consecutive days). The last brew (which is still in secondary) is only down to 1.028, I'll talk you through the last brew:

Brew Date: 21/11/10
Style: Germ Pils
Yeast: Saflager 34/70 11.5g
Vol: 22L
OSG: 1.058
Pitching Temp: 24C (approx 1030 that night)
Wort Temp: 13C (The next morning) Airlock bubbling away

01/12/10
Temp: 13C
SG: 1.028 Airlock bubbling slowed down so transferred to secondary.

07/12/10
Temp: 13C
SG: 1.028

09/12/10
Temp: 13C
SG: 1.028

Secondary Airlock did commence bubbling but only for 24 - 48 hours. I still have the beer in secondary.

The wort taste and smell ok, will still keg it and drink it but would really like to work out what is going wrong.

Issues I know I need to fix but don't believe this to be the reason for the above results.

- My current immersion chiller only gets the wort down to 35C, I then moved the fermenter to the fridge and left it as long as I could (couple hours) as concerned about infection if I leave it to long. I am improving my wort chilling before the next brew, currently use copper coil in kettle with garden hose buried in ice in esky, am going to get second copper coil that will go in esky with ice, this should keep the chilling water colder longer increasing speed at which wort cools and should also cool wort closer to pitching temp.

The reason I don't believe this to be the problem is because I did it this way previously and it still fermented out.

I have scanned previous threads to see if anyone else has posted this problem to no avail, so if you have gone through this or have any advice it will be much appreciated.

Cheers,

Sean

Thanks to everyones advice on my attenuation issue, several things came out of it and my brewing efferts on Sunday have reeped the benefits.

Firstly I went down to bunnings and bought 18M of copper pipe, got it for half price as it was out of its wrapping and slightly out of shape. I made a new two phase immersion chiller, put my old shorter copper coil in the esky with ice and then connected that to the 18M coil in the kettle, wort down to 24c in 30 minutes. One point though, don't put ice directly on your copper coil as it freezes any water in the coil, it took me 5 or so minutes to defrost it and get the water flowing, maybe ice water next time.

Secondly I tested my thermometers (I have two) and one of them displayed 85c at boiling point. They are both exactly the same so I don't know which one I used in my mash previously, my guess was the faulty one which would have meant I was mashing at around 50 - 55c for 60 minutes.

Thirdly I used two packets of yeast (23gms) and rehydrated them. My rehydration method was a teaspoon of brown sugar dissolved in a cup of hot water (sterilised), wait to water cools to 20c, pitch the yeast, aggitate, cover in glad wrap and let sit, as soon as it is frothing away its ready to pitch. I know there are probably 100 differents methods and beliefs but I was giving this one a go and it seems to have worked, my fermenter started bubbling away within hours of pitching.

So problem are appeared to be two fold, one - incorrect mash temperature and two - under pitching. So thanks again and happy brewing.

Cheers,

Sean

 

[[email protected]]

Um if the thermometer was reading 15 C below actual temperature then you would be mashing at 80-85 and reading 65-70, not 50-55. This definately explains the high final gravity.

 

[WarmBeer]

Um if the thermometer was reading 15 C below actual temperature then you would be mashing at 80-85 and reading 65-70, not 50-55. This definately explains the high final gravity.

Yup.

See my post #8, above. Nailed it! ;D