Tuesday, May 19, 2009

Where Did It All Go Wrong?

Last night I bottled the stronger of my smoked chocolate stouts, it had an OG of 1.045 as a result of my decision to just chuck all the steeping malts in at once rather than having about 100g of each knocking around the flat. The final gravity this time was 1.022, giving me an ABV of 3.1%, which while not being "to style" is better than the other version.

Although I am not particularly worried about the low alcohol content, I would appreciate some advice from more experienced brewers as to why this beer didn't ferment as well as the last two. So here is the recipe for the stronger version, with the weights for the weaker in brackets as I followed exactly the same procedure for both beers:
  • 500g dry malt extract
  • 250g (150) rauchmalt
  • 300g (200) black malt
  • 50g unsweetened cocoa
  • 25g whole Fuggles
  • 10g whole Fuggles
  • 10g whole Fuggles
  • 5g whole Fuggles

I steeped the rauch and black malt for 30 minutes in water at about 55° celsius before sparging the grains with water at the same temperature to give me 2 litres of wort, to which I added the extract and brought the whole lot to the boil.

Once I had a decent rolling boil going I added the cocoa and the first hop addition for a 60 minute boil, and further hop additions at 30, 15 and 5 minutes, before adding the wort to previously prepared water in the carboy to make a batch of about 4 litres.

Cooling the wort took about 30 minutes.

With the yeast, I used a Wyeast Irish Ale Yeast in a smack pack, I pitched half into each carboy, having followed the instructions on the label, although for such a small batch I don't make a starter. Fermentation kicked off about 36 hours later, as it had with Limelight and EDM, and was very vigorous for the first 48 hours or so before slowly down and after about 5 days just bubbling once every minute.

So any theories, any ideas as why such a low ABV?

Posted by Velky Al at 1:51 AM
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7 comments:

  1. What brand malt extract are you using? If it is Lowlander (or laaglander) DME then that could be a problem too. That DME seems to be less fermentable than others.

    Also, the Malt extract will give you the sugars that your yeast can munch away on. The specialty grains, like Black malt, will add something to your OG but won't supply edible sugars for your yeast. I think you just don't have enough fermentable sugars.
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  2. oh yeah, and you won't be getting any fermentable sugars from the rauchmalt unless its mashed rather than steeped.
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  3. The malt extract was from a local Czech supplier called Mistr Sladek. I had read that it was ok to steep the rauchmalt, which I did for my smoked mild before - purely for the flavour rather than any sugars.

    So basically I should up the extract next time?
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  4. One obvious thing to look at is your temperature: is the yeast warm enough during fermentation?
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  5. The room I do the fermentation in is at about 18 degrees pretty much all the time. I didn't have any problem with the Scottish Ale and Belgian Wit yeasts.
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  6. 1.022 is about where my own (chocolate stout) was last time I checked. I will probably bottle today after taking another hydrometer reading. The difference for me is that my OG was much higher so it should be a strong stout. Perhaps the cocoa is keeping it up? How fermentable is cocoa? I know there was plenty of cocoa in my primary before I racked to secondary to help it clear.
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  7. I've just scaled up these hop rates for my brew - it is very hoppy.
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