Higher than expected final alcohol levels

[Lesinge]

Hi all. Switched to AG about 8 brews ago and really loving it - in fact I spend half my waking day thinking about recipes and ingredients :) . What I have noticed though is that using Greg Hughes book as a source I am achieving higher than expected OG readings and given that I achieve around 1010/1012 FG the beers are turning out in some cases 6.2% rather than 5.2%. Is this just because I am achieving better efficiency with my sparging? and if so is this a bad thing in any way? I sparge with about 17.3 litres for a final boil starting point of 27 litres (23 final in the FV). By my own rule of thumb each kg of base and other malts should each give me 1% final volume. I measure the 5kgs or so in and at the end get a beer over 6%. It is not something to complain about but interesting to know. Occasionally I know the reason, if I end was a lower volume from the kettle but on others its a mystery!

Could this be because Greg is calculating using Wyeast and I am using Fermentis?

 

[geetee]

This should be easy to test.
Your set up, temp control, configuration et al will be different to his so don't expect exactly the same result even down to the grain being used and how it is crushed.

if you are consistently getting higher ABV then this suggests a systemic, ie. one way reason for this to happen, not just random.Work out your efficiency and see what it is, this may tell you if it is better than the Greg Hughes or not (not sure if he quotes his efficiency?)
If your efficiency is better then for your next brew scale back your ingredients, try to keep your volumes to what your target is and you should see a corresponding fall in the final level of alcohol.You will then be able to adjust each recipe accordingly and be able to predict the extract.

Yeast may be a small factor but if you are getting almost full attenuation should not be the main cause.

 

[Covrich]

Yes as Geetee says, pump your numbers into software like brewmate or what not, if you are consistenly getting higher efficiency say 80% you could scale back on your base malt to suit the OG.. A consistent efficiency is really ideal so that way you can predict what you expect.

The yeast though will play its part, if you dump US05 in for example and you will attenuate at 80% to 1010 or 1012, whereas if the yeast is something which is lower attenuation such as a ringwood or boddingtons yeast these can be 65 or 70% leaving more body behind.. and gravities 1015+..

 

[TheRedDarren]

Yup, as Geetee and Covrich say, there are many factors that combine to give you your FG, but the biggest single factor is your efficiency, otherwise known as 'brew house efficiency'. When creating a recipe with software the first figure to input is your brewhouse efficiency, the software then works out quantities to arrive at your desired FG/abv.
Of course other things come into play after this such as mash temps, yeast health and attenuation etc etc

 

[Lesinge]

Thanks for the info guys, I think I may be able to save myself money and get another brew out of the 25kg bags of Maris Otter I buy if I bring down the KG of the base malts. Excellent!