Another dumb question about sparging

[Reidman]

I am a tad confused on how much of the sparge runnings I am supposed to collect. Am I wrong in thinking the more wort you collect and boil down the higher the eventual OG will be once you get to your target volume of 5 or 5.5 gallons..?

I think this caused my low OG in my last batch. I collected the 7 gallons in brewpot according to beersmith but I probably left 2-3 gallons of wort in the mash. Should I have collected this extra wort in another pot and just add it to the boil when the level gets down..? Seems a waste to leave good gravity wort in the MLT...

Please enlighten me oh mighty AG brewers..

I plan on brewing next weekend and don't want to make the same mistake.

 

[Drunkensatyr]

Really it all depends on the hydro reading if you are fly sparging. If you are batch sparging, then you should be calculating out grain absorption and using the correct qty.

 

[zoebisch01]

If you are fly sparging you want to hit it so that you have no wort left in the tun once you have collected the proper amount. What it translates to is that (obviously) anything left in there is potential going to waste (if you don't use it for something else like starters or something). If you have a large enough boil pot you can always collect it all (say you overshot by a gallon) and then boil down extra long to get your target volume. I always try to collect 7 gallons of wort as I usually shoot for 6 gallon batches...unless it is a high gravity brew in which case I usually collect 7 (or slightly more) and boil down more, the trick being that the recipe is planned around the 5 gallon volume.

 

[zoebisch01]

Keep in mind too, with fly sparge (not sure how it translates in batch) that your last runnings are really really low gravity and not nearly as important as at the beginning of the sparge but they can add up to slight inefficiencies in your process.

 

[Reidman]

Sorry, I guess I should have stated that I batch sparge.

 

[Drunkensatyr]

0.12 Gallons of water per 1# grain is lost to absorption on the dough in. Your sparge will not lose any to speak of. That with your water/grain ration will get you on the numbers. If you are really worried, then do 2 half sparges... can't say I prefer this method, but some use it.

 

[ajf]

If you are batch sparging, as you suspected, you need to run the MLT dry at the end of the batch. Rather than collecting a large amount of wort and then boiling down, you can also use less sparge water.

-a.

 

[Brew-boy]

I dont think you ever want to run your grain bed dry in fly sparging. You always want to keep at least 1" of water on top of the bed when sparging. Yes you will loose a few gallons due to this, but hey water is cheap compared to good home made beer.

 

[drayman86]

I dont think you ever want to run your grain bed dry in fly sparging. You always want to keep at least 1" of water on top of the bed when sparging.

I would tend to agree with the above. We've only ever fly sparged, never run the grain be dry, and have always hit our target OG's with the system running about 80% efficient.

 

[DeadYetiBrew]

Sorry, I guess I should have stated that I batch sparge.

The mash water will always be your highest OG, we try to keep the volume around 1/2 of what is needed for the boil (60 minute boil we add a gallon to what we want our final to be.). Then when you sparge you add the water to the grain and stir it some to get it to absorb the sugars left on the grains, then you drain this, when added to your boiler you should essentially have more liquid than you want in the end... You want to drain all the liquid from the mash AND sparge, if you miss your volume you miscalculated something. For example:

You want a 5 gallon batch:

Boil Volume: 6 gallons (that's our personal evaporation (1gal an hour))
Mash Amount: Should be half of what you want your boil volume to be PLUS your grain absorbtion
Sparge Amount: Half of your boil volume (since the grain has already absorbed water from the mash you need not worry about calculating this in)

My brewing partner actually made a simple Excel spreadsheet that calculates everything fairly well, we've hit our boil volume and batch volume very well with it, and get 75% efficiency, i'll post it when i can get it from him...

Note - If you have 6 gallons, and your evaporation rate is 1 gallon an hour, then the final will be 5 gallons of wort that has a higher gravity than the 6 gallons, because the liquid evaporated NOT the sugars.

 

[Bobby_M]

I would tend to agree with the above. We've only ever fly sparged, never run the grain be dry, and have always hit our target OG's with the system running about 80% efficient.

AJF said: If you are batch sparging, as you suspected, you need to run the MLT dry at the end of the batch.

I agree with that. First, decide how much wort you're willing to deal with in the kettle based on boil off and hop bill absorbtion. The amount of water you put into the mash is based on your grain bill. Drain your first runnings after your saccrification rest into a vessel that you can measure volume with (if you don't have measuring stick for your kettle that is). I like the ale pail bottling bucket as it has half gallon tick marks. Let's say your first runnings nets you 3 gallons. If you wanted 7.5g in your pot, you have to sparge with exactly 4.5 gallons.

Even in fly sparging, I'd imagine you'd want to stop adding new water towards the end of the sparge if you're reaching your desired runnoff volume. I really don't know. I'm just speculating.

 

[DeadYetiBrew]

here's the brewsheet

Mash Sheet

Just put in your boil time, wanted volume, lbs of grains, and stuff, it'll calculate how much water you need for mash and sparge...

 

[Reidman]

Thanks guys for all your input. That's pretty much what I thought is that I used either too much mash water or sparge water since I had some left in the mash after hitting my pre-boil volume.