I keep getting lower than expected original gravity.

[Jack of all biers]

Neither method is wrong. Speed of your sparge (I assume you are fly sparging) is the key. Keep it to around 1L/min and you will have a nice clean sparge (after vorlauf of course) and an improved efficiency.

EDIT - of course the pre-determined volume method works only if your measurements are accurate and temperature compensated for differing volumes etc. It worked for me on my last brew with a mash efficiency of 97.71% into kettle and almost the exact volume I wanted (300ml extra into kettle for a 58L pre-boil, but I added 600ml at the HLT for errors)

 

[dblunn]

Thanks for the reply Jack, I have been using the predefined volume in the HLT method as it allows me to add salts and acid to the sparge liquor easily (I use Bru'in water spreadsheet + Beersmith). The only problem is I have to keep a close eye on the level because when the HLT runs dry the HEX overheats (also not great for the pump but there is still quite a bit of water sloshing about in the pump head to keep it lubricated) and last weekend that happend leaving a nasty discoloured section on the HEX element where the water level fell. If possible I will add a second sensor to the HEX housing to keep the water from boiling. I'm not sure there is room though and of course I will need to re-learn my software and make changes to the controller.
Regards, Dave

 

[Jack of all biers]

Thanks for the reply Jack, I have been using the predefined volume in the HLT method as it allows me to add salts and acid to the sparge liquor easily (I use Bru'in water spreadsheet + Beersmith). The only problem is I have to keep a close eye on the level because when the HLT runs dry the HEX overheats (also not great for the pump but there is still quite a bit of water sloshing about in the pump head to keep it lubricated) and last weekend that happend leaving a nasty discoloured section on the HEX element where the water level fell. If possible I will add a second sensor to the HEX housing to keep the water from boiling. I'm not sure there is room though and of course I will need to re-learn my software and make changes to the controller.
Regards, Dave

I think you have answered your question for yourself then. Given the lack of difference of resultant volume between the two methods, one is pre-measured and the other measured at the end (and likely more accurate if attention is paid), your only issue would be your salt/acid additions. Without getting into water profiles etc, I will assume that you need to add salts/acid to your sparge water and that your HLT volume is large enough to carry the extra capacity of continuous flow. If this is the case then I'd suggest making up more salted/acidified sparge liquor. The extra it will cost you in salts and acid would be minor compared to the cost of burning/blowing your pump/HEX.

It all depends on your system set up. Your system sounds like the continuous flow method would be best so as not to damage your equipment. Of course if measuring into the kettle is a problem (which it was for me) then $2-3 for a piece of oak dowel and measure the notches at relevant volume increments is a cheap solution, or a sight glass on your kettle, or a ball valve cut off system to stop the flow/pump/HEX at the required volume setting. The last one would be more expensive, but if being present for the entire process is the problem then it may be the solution. I'm sure there are other ideas out there.

Ah, home brew. Its so simple and cheap to get into and then we want more........

 

[jibba02]

The Joe White malt is probably half your problem (so I hear), try another brand. Also try not using your element during the mash, you may have to insulate it well.

Yep had 80kg of the stuff and had the same problem. Now I never use any Jw malt and hit my numbers every time ( give or take)

 

[dblunn]

I think you have answered your question for yourself then.

Yes, you're right. I had a play with Bru'in water and I can up the sparge volume and it calculates the correct additions for that volume without any effect on the mash additions. Although if I up the mash volume changes pH ect. so that wont work but dough in is quick and it is not a problem to hook up the hose (I underlet) and wait for it to pump in.
Thanks again, Dave