Pre Boil Gravity

I made an all grain recipe (Bitter and Twisted) which said the pre-boil gravity should be 1.036 but mine was only 1.026.  Any advice on what I did wrong or what I should do in the future ?

Paul

Your gravity reading is only part of the equation.  What was your volume versus what the expected volume was supposed to be?

Then add up the gravity points: 

(Target OG-1)*1000 * target volume = expected gravity points
(Actual OG-1)*1000 * actual volume = actual gravity points

If the numbers are pretty close then the issue is a volume issue and you need to look at your equipment profile

-- you are extracting the correct amount of sugars based upon your projected efficiency
-- your water volumes are too high

If the actual gravity points is greater than the expected points, then your equipment profile is off and you had a better conversion/extraction efficiency than you had planned on

-- your water volumes are too high
-- you need to adjust your profile for a higher efficiency

If the expected gravity points is greater than the expected points, then you had poor conversion/extraction efficiency

-- there are a number of issues that lead to low efficiency.  So breaking it down further:

*  if your water volumes are close (predicted vs actual):

--  look at the crush of the grain, it may not be fine enough
--  look at your mashing time, you may not have enough time for extraction of the sugars once converted
--  you may not have fully dispersed the grains into your mash water, leading to dough balls
--  your sparge was poorly performed -- not enough mixing, contact time, channeling of the sparge water, etc.
--  you will need to adjust your recipe efficiency to reflect your actual results

*  if your actual water volume is much greater than your predicted volume:

-- the above list is still applicable, but you also need to look at your equipment profile and readjust the water volumes

*  if your predicted volume is much greater than your actual volume:

-- you really have a mess. Start by adjusting your equipment profile for volumes and actual efficiency
-- follow list above for troubleshooting your process

Thank you for your reply - I'll work through the list.

Paul

Hi Paul,

If you got your grain crushed I can all but guarantee the crush was too course. When I got my own grain mill my yields dramatically increased. For some reason Home brew stores are so petrified of stuck mashes that a lot of grains get through un-crushed. there are several good threads on this forum concerning how to set your mill and what a good crush should be.

Thank you - I crushed my own and think I had the gap too large.