Do I Need More Yeast?

[Truman42]

Just finished brewing a Scottish Ale and ended up with 16 litres at an SG of 1.072.

I pitched a Wyeast smack pack last night of Scottish Ale 1728 and am fermenting at 18C.

Since then Ive been reading up on all things yeasty to further my knowledge on this subject as I want to start playing around with starters, slants etc.
I was playing with Mr maltys pitching rate calculator which says I should have had 2.1 packs of yeast without a starter.

What I dont understand here is that wont yeast just keep multiplying and growing as long as there's enough food for them? So wont the numbers eventually grow to what would be required, even if fermentation takes a bit longer as this happens?

Anyway lesson learned for next time but with this one do I..

Leave it and see how it goes?

Add another pack of 1728 and if so when, after it has settled down?

Any other suggestions?? Thanks in advance.

 

[.DJ.]

others can give a more details account but basically "underpitching" causes the yeast to become stressed and produce undesireable flavours.

 

[QldKev]

Taken from http://www.wyeastlab.com/com-pitch-rates.cfm


A low pitch rate can lead to:

* Excess levels of diacetyl
* Increase in higher/fusel alcohol formation
* Increase in ester formation
* Increase in volatile sulfur compounds
* High terminal gravities
* Stuck fermentations
* Increased risk of infection

 

[Truman42]

Ok so whats my best option to fix this?

 

[np1962]

What I dont understand here is that wont yeast just keep multiplying and growing as long as there's enough food for them? So wont the numbers eventually grow to what would be required, even if fermentation takes a bit longer as this happens?

Basically- NO,
Yeast will only multiply while there is enough available oxygen and the alcohol level is relatively low. Many more factors but these two are the easy ones to understand.
Yeast produce sterols to keep their cell walls healthy and need oxygen to do this, after budding several times the amount of oxygen available will be too low and they will not multiply beyond this.
This is why using a stir plate will give you a higher cell count than just letting your starter sit undisturbed as it introduces more oxygen to the wort over time as well as keeping the yeast moving.

This is also why using the 'double drop' technique can get you better attenuation and a faster ferment. Bribie's 'thrashing of the wort' after 16-18hrs works the same way and would be something you could try if you are really worried about your situation.

I'm no scientist so my explaination is pretty basic but should help hopefully.
Cheers
Nige

 

[MarkBastard]

3rd thread from the one batch of beer?

 

[Truman42]

3rd thread from the one batch of beer?

Well if I posted different topics in the wrong forum, then Id have people complaining about that.

And the other two topics weren't related JUST to this batch of beer but problems I am having in general.

Sorry I thought this was a forum..

 

[Mayor of Mildura]

How's the beer going Truman? Has it kicked off yet? Even though theoretically not optimal I would happily pitch a newish smack pack into 16L of 1072 wort and not give it a second thought. I reckon the beer will turn out fine.

 

[Truman42]

How's the beer going Truman? Has it kicked off yet? Even though theoretically not optimal I would happily pitch a newish smack pack into 16L of 1072 wort and not give it a second thought. I reckon the beer will turn out fine.

Mate, it took a few days to finally kick off, (I usually get good activity within 24 hours) and is bubbling quite slowly compared to other brews Ive done, although I do have my fridge set to 18C.
Hopefully it will be okay. Ive wanted to do a Scotch Ale for awhile now so would be spewing if Ive wasted my time.

Thanks for the advice.

 

[pk.sax]

I say brewers jumping to AG brewing early are entitled to a few extra threads
Just so much to absorb if doing that.
Stop heckling him, Ted will be angry

 

[Truman42]

I say brewers jumping to AG brewing early are entitled to a few extra threads
Just so much to absorb if doing that.
Stop heckling him, Ted will be angry

Thanks mate...yes a lot to abosrb, I read as much as I can and ask questions but you dont remember everything your told and slip up on a lot of things. The more I do and the more I ask the more I will learn.
My first few Biabs I used to follow a printed guide. Now I can do the process without the guide but I still need to learn about yeasts, starters and all of that.

Where is Ted? I miss him and his ways.. :icon_cheers:

 

[WarmBeer]

You'll be fine.

The beer might not be the best it could have been, given exactly the same wort, but it will still be great beer.

Given you're pitching into only 16lt of wort, it's the equivalent of 1.25 packets into a 23lt batch.

RDWHAHB :icon_cheers:

 

[Truman42]

RDWHAHB :icon_cheers:

I have no idea what that stands for???? Apart from the AHB at he end.....

 

[QldKev]

I have no idea what that stands for???? Apart from the AHB at he end.....

Check out http://www.aussiehomebrewer.com/forum/inde...;showarticle=17

 

[Truman42]

Check out http://www.aussiehomebrewer.com/forum/inde...;showarticle=17

LOL..Thanks, that will come in handy..