Lots of yeast but little attenuation

[Stu6363]

I made my first extract beer, no kit involved, over Christmas. 500g muntons light dme boiled in a gallon of water treated with Camden tablet for an hour. Hop additions 5g a 60m 5g at 15 an 5g 5m.

I rehydrated a 6g sachet of wherry yeast thinking that would easily ferment 1 gallon.

I didn't measure the sg but 1 gallon water, 500g dme and 50g sugar gave a predicted sg of 1047 using an online brewing calc.

Fermentation Took off like a rocket for 2 to 3 days (temp at 21) thought I'd nailed it.... left it almost 4 weeks in primary and go to bottle it only to see fg of 1030?

Tried warming and stirring to no avail. Drank 4 pints tonight was very sweet but feels like it's stronger than a beer that has gone from 1047 to 1030.

My gut feeling is either the yeast or poor aeration being the problem. (Shook demihohn only for 1 min)

Any ideas where I have gone wrong or advice very welcome.

 

[Dutto]

For me, the three main suspects are:

• Problem with your hydrometer.
• Yeast died due to old age and/or high ABV? (The high ABV could be caused by a volume loss of 10% with an hour long rolling boil.)
• Lack of yeast nutrients. (I always stick a teaspoonful in there!)

I have to say that if you drank four pints of it before Posting, I can't see it being my first idea!

 

[MyQul]

Imwith dutto on this, I think it might be your hydrometer (or measuring yo sample). Did you get a lot of trub in the gravity sample as this will effect the measurement. The last 5L brew I did as OG 1.057 and I used 3g of yeast (unhydrated) and almost hit my FG (I was 3 points off so I think I could have done with a bit more yeast)

 

[Norfolk79]

I'm guessing as Wherry kits are famous for getting stuck, would the yeast used be the same one as in the kits, and hence has got stuck?

 

[Sadfield]

One for the Winemakers to confirm, isn't 1 Campden tablet per Gallon the sort of dosage used to stabilise wine? If so your yeast could have been seriously inhibited. This might explain why rousing the yeast didn't work, if it had been slowly killed off by the sulphite.

 

[Stu6363]

Thanks for the replies guys. I have calibrated my hydrometer using water and have adjusted for this in my measurement, also there wasn't much trub in the sample taken.

It could be old yeast and as it was from a Woodfordes Wherry kit it could be the case of a stuck fermentation as is common with the kit perhaps. I will check the best before date on the Wherry kit (which I still have) to get a very rough age of the yeast.

I didn't note how much of the campden tablet I used but I think it was a half tablet. Which is probably around 10 times more than is required when I read the recommended dose is 1 tablet per 20 gallons

Oh well all lessons to be learned for my next brew.... less campden and a good quality yeast.

 

[terrym]

If you can't taste chlorine or chloramine in your tap water then don't use campden tablets. I used to use it, but stopped and noticed no difference, but then only rarely does my water taste out of sorts.
And there is nothing wrong with the Wherry range kit yeast. But at 6g there isn't enough to guarantee a successful fermenation of a 20+ litre brew. Used for smaller brews, like I and others have done, its fine. If your yeast has failed to work it may be age, or just a duff batch which is probably highly unlikely but not unheard of.

 

[Thumper]

If my understanding is correct, the campden shouldn't have inhibited fermentation if you added it to tap water before brewing. It should have reacted with the chloride and chloramines (and does actually create a yeast nutrient when it reacts), and I've been told you can't actually add too much.

 

[Sadfield]

NaHSO3 + Cl2 + H2O ----> NaHSO4 + 2HCl

That doesn't sound very logical. Surely if you have x number of chlorine molecules you need the same number of sodium bisulphite and water molecules to react with it? Any excess sodium bisulphite and water molecules should remain. And, react together to make Sulphur dioxide?

I guess the boil would gas it off though.

 

[Thumper]

I must admit that was my first thought. But it was one of the regulars here who said you can't add too much. I think StrangeSteve? But perhaps he meant that you can't realistically add too much to a 23l batch, rather than it's physically impossible to add too much.