Experiment - Advice

[Mr Majik]

Evening all

First of all, sorry no photos i will try during some brewday but had too much going on today.

So, my second brew and it is far "by the book" as im figuring it all out from the olden day methods... And a touch of "learning by mistkes"

Any how, the malting process went ok. As did making my wort... Exept...

Problem 1)
my gravity is 1.082! However im sure alot of this will be "unfermentables" as its my first ever home made batch if malt, and my first go at AG. still have a few bugs to work out (next batch of malt already started! ) ill keep an eye on the G's as the weeks go by if it gets going..

that brings me to...

Problm 2) no action.

I preppeared my yeast (simply "wilkos ale yeast") in water of around 20 ish, then pitched it in to my FV full of wort that was about 25 ish. 2 hours later and not a bubble.

My plan is waith until tomorrow night, if no action throw another bag of yeast in.

Any thoughts on this?

 

[PD]

depending on many factors it can take 12-24 hours for the yeast to get going.

 

[Mr Majik]

Cheers PD, i'll give it some time then. I suppose i'm impatient as my first brew a couple of weeks ago (using dme) pretty much exploded when i pitched!

 

[jonewer]

2 hours is very quick to see any activity but If theres still nothing then dry pitch another packet asap.

 

[pittsy]

if you have 1082 i would split the brew into and add some water (boiled and cooled to lower og) and that's prob why yeast ain't working , you need 2 packets for that high a gravity.

 

[WelshPaul]

I did a brew a couple of weeks ago using Nottingham yeast and it took the best part of 2½ days plus another sachet to get going, most likely due to the cooler temperatures at this time of year. What temperature is your wort?

 

[just_steve]

if you have 1082 i would split the brew into and add some water (boiled and cooled to lower og) and that's prob why yeast ain't working , you need 2 packets for that high a gravity.

Interesting :hmm: . I would guess some strains of yeast would struggle if the ABV managed to reach 8 or 9% but I never thought about yeast finding it hard in an initial high gravity... What could that be down to exactly? Osmosis being slow causing the yeast to hydrate themselves too slowly perhaps? Any other ideas? Sorry for being too much of a biologist :geek: .

 

[just_steve]

I have an answer thanks to a book I got for Christmas:

Firstly, the osmotic pressure on the yeast at high sugar levels means the yeast struggles to metabolise any nutrients available.
Secondly, towards the end of fermentation, the osmotic pressure has changed a lot and also alcohol toxicity becomes a factor which puts stress on the yeast.
Thirdly, oxygen levels in high gravity worts are particularly low as oxygen doesn't dissolve well in these kind of worts. So initial propagation of yeast would be rather slow unless you pumped in pure oxygen for a short while at the start of fermentation.

The biologist is now satisfied :) .