Thursday Barrelling Day

Today I decided to empty the Brakspear Bitter into a pressure barrel. This brew was made on the 10 Jan 11 so it had 10 in the fermenting vessel which was in the temperature controlled fermenting cupboard. The Original Gravity should have been 1.035 but I could only manage 1.032. The final gravity was 1.006 and should give an ABV of about 3.4%. I still can't figure out why the original gravity of my brews has been dropping. Could it be that the mineral water I am using to top up the wort to the final volume of about 23 litres is somehow effecting the OG. I can't see how but am open to suggestions. Ran off the wort into the pressure barrel on top of 77 grams of light dried malt extract powder. The recommended way is to first dissolve the malt extract powder in about 250 mls of boiled wort. However, I find this unnecessary and can discern no difference in taste, colour and clarity. I then put the barrel into the fermenting cupboard where it stay for 2 or 3 days before moving it to the garage for conditioning. The first tasting is very promising.