Overshot the ABV / attenuated too far

Well, today I racked my belgian blonde it into the secondary (better bottle) after 5 days in the primary. I am going away on holiday on tuesday for two months, so I will leave the carboy in the fridge while I am gone to let it clarify and cold-condition, hopefully resulting in crystal clear beer.

The thing that struck me as a little surprising, however, is that I checked the SG today and it's 1.006!! It was 1.064 to start, which means I got about 90% attenuation. I was shooting for a lot less than this, i was hoping for beer about 6% abv, and now I've got 20 frikkin litres of 7.6% ultra-dry blonde.

I step mashed 146 and then 156, no mash out. Aerated really well and pitched a massive 4L starter, all to try and boost attenuation. Unfortunately, just like how I overshot the efficiency I planned for in the mash, I've gone and way overshot the attenuation too.

25.5L batch
6kg pilsener
500g demerara sugar
60g saaz for 90min
40g saaz for 30min
Recultured 'la trappe' belgian yeast, 4L starter
Pitched at 16C, rose to about 22C during fermentation

What a nightmare. Can I dilute it down before bottling? Any suggestions? I wanted an easy-drinking beer, something like a clone of De Koninck blonde, not bone dry jet fuel.

An easy trap in making Belgians is not accounting for the sugar correctly. It always attenuates 100%.

You can certain dilute it. I would try a glass with four parts beer and one part carbonated water. That would hit 6%.

David,

I did account for the sugar, I don't think that only 7% of the fermentables being sucrose is what boosted attenuation that far?

I read this article: Attenuation - BrewWiki for ideas, and then I did everything to try and boost attenuation - aerated really well, mashed for attenuation, pitched lots of yeast, mashed for 90mins and only used base malt. I think the biggest factor must have been the mash schedule, next time I will try mash at a higher temperature.

I've bottled one bottle diluted to 6%, along with another one neat so to speak - so I will see how they turn out when I get back from holiday before I decide what to do with the rest. I might just leave it the way it is, and shoot for a weaker, sweeter beer next time round. Bit more of a golden strong now than a blonde, the hydrometer sample did taste quite good.

Adding water will certainly reduce the alcohol content but it will not improve the specific gravity. If you were looking for a specific body/mouthfeel from a higher finished SG you might have benefited from a mashout. The mashout is supposed to stop eny further conversion from starches and complex sugars to simpler easier to ferment sugars. As long as the enzymes are active they will continue their work.