High Gravity beer question

[quixoticgeek]

I have a recipe which requires 6.5KG of Maris Otter in a 23l batch, giving a OG of 1.072 once the adjuncts are added in.

Is it reasonable to expect this sort of yield from a single mash and batch Sparge? Radical Brewing suggests that things go a bit weird once you pass the 1.060 mark. Can anyone shed any light on this?

Thanks

J

[Morten]

That would be about 80% efficiency, that is pretty high by most homebrewers.

I have only batch sparged once, so I am not an expert by any meassure.

[bigdave]

It's likely to finish around the 7% marker, which is easily viable with normal yeast.

[zgoda]

In my brewing after 1.065 it's better to assume 75% efficiency. 80% is normal for standard gravities. With batch sparging, but I'm crushing grains on my own.

[Barley Water]

I'm using a Gott cooler mashtun with a false bottom and the highest gravity I can get is about 1.085 in a 5 gallon batch. I batch sparge and frankly I don't think I loose much yield doing that. What can happen if you fly sparge is that you end up getting channeling which will reduce your yield (and potentially cause other problems as well which is one big reason I batch sparge). If you end up with a 1.072 wort most ale yeasts will ferment it however if you don't control things you could easily run into other problems (like excessive esters and phenols including the dreaded fussels which really can screw up a beer). Make a great big starter (or use the yeast from a smaller beer), oxigenate the wort and control the fermentation temperature. Depending on what style of beer you are trying to make one trick to employ is to add some simple sugars to encourage complete attenuation and dry the beer out (that's what our buddies in Belgium do with those monster beers they brew over there). You really want to avoid "hot" tasting beer, no style I can think of benefits from those sort of flavors plus they will give you a hell of a headache.