First off, lone brewer in an isolated mountain town at +8,000ft, so most of what I have learned has been from books and youtube videos…so be warned.
Made the jump to all-grain a few weeks ago and have run into a consistent problem. My OG cannot get above 1.040. At first I thought it was my refractometer or hydrometer, but they work fine when I was making extract brews. So i began taking samples and readings throughout the process. WHat I found is that I am losing about .020 or more gravity points during the sparge process and need help in figuring out why and how to prevent it!
System and Method:
Recirculating Pump System with 15g mega pots
Average recipie was 14lb of grain to 17qt of water
Mash at 150 for 60 minutes (or till iodine test show good to go)
Sparge 4g of water at 170 for 15 minutes
Transfer 6g to boil and boil for about 60min at ~196 (Altitude boil point)
Boil off about 1g for finale volume of ~5g of wort
Issue is that during the sparge process, I am loosing gravity. When I take a sample post mash, but pre-sparge, I am hitting my targets, but post boil, I am reading a consistent 1.040, regardless of the recipe. I took pre-boil/post sparge samples, on the last two batches, and found that I was losing about .020 gravity points with sparging.
This is a hard one to trouble shoot because it sounds like you are really just missing something in the process, and it would be difficult to pinpoint without going through your entire process. A recipe calculation software is a good recommendation. There are some online ones that work really well, like this one:
You want to make sure you are hitting your temps: 150 degree mash is a good temp to hit. A good dough in ratio is 1.25 qts water to 1 lb of grain. Generally speaking, with a preheated mash tun, 170 degree water should get you there.
After the mash, 170 degree sparge water should rinse the proper amount of sugar from your grains.
pH and other issues could still be issues, but I don’t think this is your efficiency issue.
You may also look at Denny’s batch sparge technique: www.dennybrew.com
Just to rule it out…you are draining the mashtun to your boil kettle after your mash, THEN adding your sparge water, mixing it and then draining the mashtun a second time into the boil kettle right?
Edit*…if not then you are not doing a batch sparge and tbat will cost you all that effeciency. This is the only thing I can think of.
If I understand correctly you are hitting the target OG with first runnings and then when you sparge the dilution is driving your gravity down pretty far.
If that is the case you have one, possibly two problems.
First, if you are hitting your target OG with first runnings then you are missing something in the mash process because your first runnings should be well above the target OG so when you sparge you are still pulling sugars from the mash but also diluting down to your target OG (or somewhere near it).
Second, you may also be oversparging by using too much sparge water and diluting the wort too much. This might be a problem while the mash issue is a near certainty.
Here are some things you can try fixing:
Check your recipes against software to ensure you’re targeting the right OG. If you are using software then try a different website or software.
Is your thermometer accurate? Are you sure? Many times thermometers drift and can be considerably off. (I have a floating thermometer from a homebrew shop that’s about twelve degrees off.) Mashing at 142 rather than 150 is not going to be the same mash.
How is the crush on the grain? A poor crush can result in poor conversion.
What about your water? If the ph or mineral profile is off you can also have poor conversion.
On my system, with my efficiencies, I would need to sparge with 4.82g to hit a a preboil gravity of 1.06 for 14# of base malt, then boil off about 1g to hit 5 gallons of 1.071 wort post boil (via beersmith.) If you only use 4 g sparge, you are leaving sugar in the tun. Are you accounting for tun loss, boil off and cooling losses in your process? Not sure these would add up to a 20 point loss, but just kind of reiterating the points abive
Are you adding the sparge water before draining some or all of the mash? In fly sparging, you should be draining the mash until the wort is a little bit above the grain level and then add sparge water to maintain that level. In batch sparging, you should drain the mash tun before sparging.