Slight under-attenuation - Is it a problem+advice

[propush]

Hello everyone!

(tl;dr: go to the list of possible reasons for under attenuation.)


So, there is a lot to read about this subject. The reason I'm asking this - Is to present my brewing routine, and then get specific advice as to why this happens in my setup specifically.

So I will bring on 3 examples. One of them didn't under attenuate. The other 2 - have.

So the first was Belgian strong ale, with O.G. of at least 1.085 (was my first brew - didn't really measure it in pin point accuracy). The yeast was t-58 @21c ambient. I have collected EVERYTHING from the brew kettle, and added it to the fermenter. Very vigorous bubbling started in about 3 hours, and the fermentation ended in a few days, with f.g. of 1.013. Pitching: I pitched one 11.5g packet of dry t-58 yeast directly in to the wort.
grain bill: base malt, and a bit of Munich.
This beer was good, and the attenuation actually exceeded expectation (1.017 was estimated).
Mash temp 67C.

I had another beer done in this method, which also attenuated well - 1.013 and expected was 1.017. This one had some dark crystal malt, and a bit of chocolate malt as well. Yeast was S-04, and it was pitched directly, like the first one. Mash temp was 67 C.

Now lets move on to the beers which under-attenuated:
1. Baltic porter. Same routine. I had too much water, and was forced to dump about one gallon of wort. O.G. was 1.066. Fermentation temp was 15 ambient, and I didn't change it at all. F.G. was 1.022 with estimated 1.018 - so we have 4 unwanted points. The beer came out amazing though! Yeast was s-04 English ale. This was a baltic porter - with about 500gr of darker malts and 400g of 40l crystal. Mash temp was 65-66c, and never less then 65.

2. Belgian pale ale that is in the fermenter right now. Used same method of brewing. Temp was 19C with S-33 dry yeast. Raised temp to 21 after 4 days. All the yeast have flocelated (I took out a shot glass of beer every day, and every day there were less yeast - until today: almost no yeast sediment in the 250ml vile I use to measure gravity. F.g. is 1.022, for three days now, with expected F.G. of 1.018. So again - 4 unwanted points. Grain bill contains 200g Dexedrine malt, with some buiscit and crystal 50l - and base malts. Mash temp was 67c.


So, from my reading I figured the fallowing could be the problems, and I wanted to consult you guys prior to my next brew:

1. I collect EVERYTHING from the kettle. I read that some of it - the sediments - is not wanted. I read the the stuff at the bottom are cold and hot brakes, and I should only have a bit of those in the fermenter.

2. I pitch directly, which diminishes cell count. If I were to rehydrate - maybe it'll solve the problem. Yet, The first two beers did very well - if I were to rehydrate, wouldn't I then end up with too many cells?

3. I don't raise the temp after 2-3 days when fermentation relaxes a bit. Maybe if I did - it would help. Didn't do it with the first beers and had no problem though.

Am I correct? Also, I used the same routine for 4 beers - 2 of which attenuated perfectly, and 2 under attenuated with 4 extra points.



What say you?

Thank you guys, seriously. I get so much help in this forum, and the advice is always so good - and results in epic beers which my friends and I really enjoy!

 

[Zacher]

1-No
2-Yes. You can lose up to half your cell count by not rehydrating. Sometimes the yeast make it through, sometimes not.
3-No
4-How are you aerating? Under-attenuation can be caused by poor aeration.

Dave

 

[propush]

Thanks Dave,


I first siphon the wort to a bucket, and splash it around while doing it. I then use the small tap in the bucket to pour it to the fermenter. I use a strainer to splash it around while I do it. I end up with a wort with big foamy head - guess it is aerated enough, or at least hope so. Do you think it is ok this way? Is there a better way to do it without more equipment?

 

[daksin]

Pouring everything into your fermentor is not a problem at all. Keep doing it because it's easy.

As for rehydrating, you should definitely do that. It's almost impossible to have too many cells in the homebrewing world. Overpitching is pretty rare.

Finally, consider aerating more. You really need to shake/splash the carboy for a while (more than a couple of minutes) to get any appreciable oxygen into the wort from the air, and that's not even really close to the "proper" amount of 8PPM dissolved oxygen, which can only really be achieved by using pure O2 and a sintered stone. It's a nice investment that will improve your beer if you're already controlling fermentation temps and pitching the right number of cells. See mrmalty.com to get proper pitching rates for liquid and dry yeast. The date of manufacture greatly influences the viability of your yeast, so it includes that in its calculations. This is a step most people neglect.

 

[propush]

Thanks daksin,

I'll consider getting equipment for that. I use a backet, so I cant splash it that much. Half of my beers did very well with the low cell count due to direct pitching. I will try and rehydrate - and see how we go from there.

 

[daksin]

Great! The best beer is a combination of lots of little improvements. You'll find your beer keeps getting better and better as you learn and improve your techniques. Cheers!

 

[Zacher]

If you are not ready to go O2 quite yet, buy a mix-stir for $25 at your LHBS. You can get the Oxygen you need for most beers.

Dave

 

[william_shakes_beer]

Thanks daksin,

I'll consider getting equipment for that. I use a backet, so I cant splash it that much. Half of my beers did very well with the low cell count due to direct pitching. I will try and rehydrate - and see how we go from there.

I also use a bucket fermenter and splasqh with no problem. Try this

1. drop your wort into the fermenter at th4e proper temp
2. pirtch your yeast and snap the lid on the bucket
3. dip your thumb in sanitizer and place it over the airlock hole
4. sit down and place the bucket between your legs.
5. Lift the far corner and rock back and forth and vigorously as you can without loosing control
6. Periodically stop and slowly remove your thumb to release the pressure.
7. continue rocking for 5 minutes or so.

It's not scientific but it works for me.

 

[propush]

Thank you all for the advice!