Poor extraction advice

[Lawrence R]

Hi
ive been home brewing “seriously “ for about three years and generally everything is drinkable and becoming occasionally very good. But I don’t think I’ve ever hit the recipe‘s OG. I brew whole grain in a single infusion in a very well insulated mash tun. I’ve double checked the temperature accuracy of the HLT and am meticulous with strike and sparge temperatures. I have to heavily dose our local water with CRS as the local RA is astronomical and I’ve checked the mash pH which is spot on, I use Palmers recommended mash water volumes. I continuously sparge very slowly over 60-90 mins. I buy my grain from a variety of dealers so i don't think I’ve one dealer with too coarse a crush. I have the same experience with ales, stouts and today, a pilsner.
Am I missing something or is this a common experience? Recirculating is not something I do much of except to clear the first runnings. Would that make a big difference? The beer is fine (the last ne ipa was a triumph if I say so myself) but this is bugging me.

 

[Clint]

What % efficiency are you getting? Is it consistant? Swapping suppliers could give you variances. Have you worked out your system losses?

 

[Lawrence R]

Thanks for coming back. Have used Brewers friend calculator to calculate some efficiencies. The last two NE IPAS I made had post boil efficiencies of 82.43% and 83.47% so looking back not as bad as I thought. But I just tried a pilsner for the first time and post boil efficiency was 69%. Not so hot. I had to stop the lauter before I got the pre- boil volume I wanted, the sg on the runnings dropped to 1.007.
the recipe called for an extended mash at lower temperatures than I’ve used previously. 50 degrees C for 30 mins, then 66.2 for 90 minutes.
Unsure of what you mean about system losses. I know the volumes I’ll lose from dead spaces in my various vessels. I also know that the mash tun has astonishing insulating properties, it hardly loses a degree over an hour. Is that what you mean? Pardon the ignorance.