Poor attenuation prob

[surly]

Hey all,

Pretty much every all-grain brew I have done (only 5 or so) has exhibited poor attenuation. My FG is always a couple of points or so higher than predicted, even when I manage to hit my OG, or adjust for the actual OG.
I have noticed my beers as being a bit sweeter/stickier than expected, which makes sense.

I am wondering if you guys could help me problem solve this?

Thoughts so far:

• Yeast not very happy. Should I add nutrient? Do you?
• Mash issues. Maybe my thermometer is inaccurate and I am mashing higher than thought? Any recommendations on a decent one that doesn't need to be screwed into the pot? (I BIAB, so would prefer to avoid potential snags).

That's all I have, please share your ideas and thoughts.

Thanks heaps,

Tim.

 

[manticle]

Yes you should add nutrient. A good beer nutrient contains, among other things, zinc which helps yeast function. You should also ensure you have adequate calcium levels in your mash.

Additionally - aerate/oxygenate cool wort well, ensure you pitch adequate healthy yeast and check all measuring equipment including hydrometers and themometers. I have a couple of alcohol/glass stick thermometers that I regularly check in boiling, iced and mid range temps and compare to each othdr. I also ocassionally rest in the fridge and compare to the stc reading of ambient.

If using a refractometer to measure final gravity, don't forget to correct for alcohol or you will get a reading that skews towards high.

 

[surly]

Cheers Manticle I have some yeast nutrient I bought for a cider, but never used it for beer, can't recall noticing brewers mention it.

Pitch rate was another I had considered, but forgot to add to the list. I typically follow the instructions on the pack, but once or twice I have pushed it.

As for Ca, I admit to completely ignoring water chemistry to this point. Maybe I should give it some thought.. Didn't realise it could affect attenuation (a sugar enzyme conversion issue?).

I use a hydrometer for taking gravity readings. Have checked it against tap water at fermentation temps and seems accurate, though not made any higher gravity solutions as controls, sounds like that would be just as relevant as the thermometer calibration.

Do you have a recommendation for thermometers? plenty of cheap alcohol ones on ebay, but have no idea about their quality.

 

[Spiesy]

Are you fermenting in a controlled environment?
What yeast/s are you using?
How much of said yeast per batch, and what is your OG and batch volume?
What sort of recipes are we talking about? Not all sugars ferment the same, and mash temp plays big part in the fermentability of your wort.

More info needed to pinpoint the cause/s.

As far as asking for a thermometer, I found that the standard Chinese electronic shitters were exactly that - shitters. They took wayyyy too long to reach the temp point - an AHB member got me onto the Hanna thermometer, it's heaps better, heaps quicker, which means I have more of a chance of nailing my required mash temp.

Also, for BIAB, you will need to do some sums to make sure your strike temp is giving you the right mash temp. Factors such as volume of water, size of grain bill, temp of grain, required mash temp all play a part.

 

[manticle]

I use basic alcohol thermometers bought from grain and grape - around $15. Have compared with mashmaster dial, stc and each other.

Yeast nutrient for cider may just be diammonium phosphate - you want to make sure it is specifically for beer. Wyeast make a nutrient.

How are you oxygenating?

 

[surly]

Hey Spiesy, thanks for the reply.

I have a fermenting fridge with reptile heat cable running through it and a probe thermostat. Probe is taped to the fermenter.

I have used US05, Windsor and Wyeast 1026PC.
For approx 22 litres of 1.060 wort I pitched a single smackpack of the wyeast (right on the borderline of the pack instructions).
" 1.048 wort 1 sachet of US05.
" 1.043 wort 2 sachets of Windsor

Recipes include 2 batches of DSGA, 1 of Dr Smurtos Landlord, 1 of DrSmurtos English IPA and 1 Better Red than Dead (this one was an all-round disaster and probably not a relevant brew to list).

I will look into the "Hanna" thermometer, thanks for the tip.

As for setting strike temp, I have been heating the water to mash temp, dropping in the grains and stirring while still heating in order to raise it back up to mash temp (have a crab cooker to keep bag off the heat). Figured a bit of ramp would not hurt. Happy to be corrected.

 

[surly]

I use basic alcohol thermometers bought from grain and grape - around $15. Have compared with mashmaster dial, stc and each other.

Yeast nutrient for cider may just be diammonium phosphate - you want to make sure it is specifically for beer. Wyeast make a nutrient.

How are you oxygenating?

Will check the nutrient.

I am oxygenating simply by splashing the cooled wort fairly vigorously into the FV, will sometimes give it a decent shake too, though this is a bit tricky with the airlock hole and a heavy FV.

 

[manticle]

And when you say 'follow instructions on the packet' which instructions and what kind of yeast?

 

[surly]

For instance, the wyeast 1026PC said to smack pack, store @ 24deg for x number of hours (think I did 4-5), then pitch directly into wort of something like 23litres with gravity of 1.060 or less.. Something along those lines, pack was trhown out over a month ago.

The Windsor, said to hydrate, then pitch at a certain rate (meant I needed 2 packs for my wort).
US05 said to sprinkle into wort, which I did.

 

[slash22000]

Thermometer: http://www.thermoworks.com/products/low_cost/rt600c.html

One of the best things I ever bought.

 

[surly]

OK, heading to grain and grape tomorrow after work. Will pick up some wyeast nutrient, some calcium chloride and a FWK to keep me busy while I wait for the thermometer to arrive.

Manticle, you are likely to be on the same water as me. For general brewing of mid range type beers (golden ales, pales and the like), do you find the addition of 50ppm of calc chloride to be sufficient?

Thanks for all the advice and help guys.

 

[manticle]

To hit target mash pH? Yeah mostly. 4g total calcium salt to mash sees me on target for mid coloured beers, single batch, 1040-1060 range.

 

[Screwtop]

1. What %AA have you been achieving using these yeasts?
Use the formula (100 % * (starting gravity - current gravity) / (starting gravity - 1))

2. What are you using as a reference for target attenuation. If using the estimated FG provided by brewing software, this is simply a figure arrived at by applying the reference AA% from the yeast database of your brewing software to the estimated OG. There are many more variables which need to be taken into account: yeast strain and health, fermentation management (pitch rate,oxygenation/aeration, temp and time), mash PH,

3. What is your strike temp and what is your saccharification rest temperature and time

4. What is the ratio of specialty malts in your recipes. Crystal and roasted malts add mostly unfermentable sugars to the wort which lowers overall fermentability.

5. Using a high strike temp with modern malts high in diastic power can result in some high alpha conversion during the time taken while stirring to reach temperature equalisation. Surprisingly some conversion in this range can happen quite quickly. Brewing software can suggest strike temps as high as 79°C when adding water to grist, often to overcome tun losses when using a large stainless steel mash vessel.

Screwy

 

[surly]

Hey all, big thanks to those who helped out and advised me on this (sorry for not getting back to you Screwy, wanted to test things before I got info-overload. I appreciate the time you took to help out.).

I just brewed a DSGA and made the following changes:
New thermometer
Added CaCl to approx 60-70ppm
bought an airpump, filter and aeration stone
Bought yeast nutrient (accidentally picked up the cider/mead one, but added it anyway)
Made a starter out of some excess wort and pitched the yeast into that a day early ~ 1L - not sure how necessary that is, but I guess over-pitching is not a massive issue with this brew as the yeast profile is pretty clean (US05).
New grain bag (ok, probably completely irrelevant).

OG of 1.047. Pitched 6 days ago, currently sitting on 1.010 for the last 2 days. This is where my brewing software said it should end. So far, the highest attenuation I have achieved to date.
The brew tastes pretty good from the hydrometer tube too, though think the citra might be a bit too fruity.

In a week or so when I keg it , I will know for sure, but it looks like things went much better.


In answer to Screwtops questions:

1. What %AA have you been achieving using these yeasts?
Use the formula (100 % * (starting gravity - current gravity) / (starting gravity - 1))

I have kept poor records on scraps of paper out in the shed, so not easily at hand ATM. But, based on IanH's BIAB excel sheet and in conjunction with the recipe writers notes, I am usually a couple of points above at FG. Hopefully, after the next few brews I will be able to see if the problem is largely solved.

2. What are you using as a reference for target attenuation. If using the estimated FG provided by brewing software, this is simply a figure arrived at by applying the reference AA% from the yeast database of your brewing software to the estimated OG. There are many more variables which need to be taken into account: yeast strain and health, fermentation management (pitch rate,oxygenation/aeration, temp and time), mash PH,

Using the brewing software and the anecdotal evidence from the recipe section on this site.

3. What is your strike temp and what is your saccharification rest temperature and time

Strike temp @ 68.5 for a 66deg mash for 60mins for the above recipe.

4. What is the ratio of specialty malts in your recipes. Crystal and roasted malts add mostly unfermentable sugars to the wort which lowers overall fermentability.

The DSGA I just made is 6.4% I think. This would be pretty typical. All my recipes have been from this site and had pretty solid reviews. Mostly DrSmurto's.

5. Using a high strike temp with modern malts high in diastic power can result in some high alpha conversion during the time taken while stirring to reach temperature equalisation. Surprisingly some conversion in this range can happen quite quickly. Brewing software can suggest strike temps as high as 79°C when adding water to grist, often to overcome tun losses when using a large stainless steel mash vessel.

Using IanH's BIAB software. The advised pitch temp has been very accurate and I have only had issues with mash temp due to poor thermometer function.

Screwy