Question about fly sparging

maltMonkey · 01-24-2008, 02:29 PM

I'm gearing up to attempt my first AG--planning a single temperature infusion mash with a fly sparge. From what I've read, you want to continue to collect wort until the SG in the MLT is 1.008-1.010.

So what do you do if your SG is high or low? If you've collected your 6 gallons or whatever and the SG is still high, do you keep collecting and plan a longer boil? And if you're a gallon short but you're lower than 1.008 do you keep collecting or just stop and add water to the boil?

**Bobby_M** · 01-24-2008, 02:59 PM

The first few times you do this you'll be discovering your efficiency baseline. You'll formulate your recipe with say 70% efficiency and then see what you end up with. If your gravity is low, you can make up with a little DME. Next time, set your efficiency to whatever it WAS on the last batch. Now you'll come in closer.

Are you sure you have the equipment suited for fly sparging? By the way, sparge until you have a reasonable preboil volume that will not require a 3 hour boil. Figure on somewhere between 1-1.5 gallons of boil off per hour. If you want 5 gallons in the fermenter, sparge until you have 6.75 gallons and boil for 70 minutes or so.

Cookiebaggs · 01-24-2008, 03:21 PM

Quote:

Originally Posted by Bobby_M

By the way, sparge until you have a reasonable preboil volume that will not require a 3 hour boil. Figure on somewhere between 1-1.5 gallons of boil off per hour. If you want 5 gallons in the fermenter, sparge until you have 6.75 gallons and boil for 70 minutes or so.

+1

I also wouldn't concern yourself with gravity of the runnings right now. Sparge to your preboil volume.

I would take a gravity when you reach the preboil volume to see if you could have sparged more (or less) to establish the baseline efficiency that Bobby mentioned.

maltMonkey · 01-24-2008, 04:58 PM

Quote:

Originally Posted by Bobby_M

The first few times you do this you'll be discovering your efficiency baseline. You'll formulate your recipe with say 70% efficiency and then see what you end up with. If your gravity is low, you can make up with a little DME. Next time, set your efficiency to whatever it WAS on the last batch. Now you'll come in closer.

OK, that makes sense....so basically if I use the same equipment and technique every time then my efficiency should always be about the same regardless of how large or small the grain bill is? Or will it be different for different grain bill sizes?

Quote:

Originally Posted by Bobby_M

Are you sure you have the equipment suited for fly sparging?

I believe so....there isn't much more equipment required outside of a sparge arm, is there?

What I have now is a 30qt hot liquor tank (I need a bigger one soon) that feeds via gravity through a sparge arm into my 60qt cooler MLT. I should be OK, right?

Quote:

Originally Posted by Bobby_M

By the way, sparge until you have a reasonable preboil volume that will not require a 3 hour boil. Figure on somewhere between 1-1.5 gallons of boil off per hour. If you want 5 gallons in the fermenter, sparge until you have 6.75 gallons and boil for 70 minutes or so.

That raises another question: if you underplan for boil off evaporation and end up with say 4.5 gallons can you just make up the difference with some more water?

Thanks a bunch...I really appreciate the help.

**Bobby_M** · 01-24-2008, 05:10 PM

Efficiency is mostly constant given everything is done exactly the same. Same relative temps, process, etc. I've found, along with others that as your intended OG goes up, efficiency does go down. I don't know what the ratio is, but it's observable.

Right, fly sparging requires some kind of sprinkling device but I'm more concerned with the extraction device. False bottom, manifold or stainless braid in there? Batch sparging might take a few variables away for the first time.

Yup, if you boiloff too much, a little top off water at the very end of the boil would be fine. You could add it to the fermenter, but a short ride in the kettle at the end of the boil ensures sanitation (if you have a way of measuring volume in the kettle).

maltMonkey · 01-24-2008, 05:27 PM

Bobby_M -- As far as the extraction device I have a 2 foot stainless braid that runs the length of the cooler.

I initially starting planning for fly sparging because ultimately that's how I wanted to brew all my beers, and I figured I might as well start with that route even if I messed up the first couple batches. I'm cautiously optimistic about the upcoming "virgin" brew, but I'm brewing some relatively small pale ales until I get all my techniques & efficiencies figured out.

**Bobby_M** · 01-24-2008, 05:41 PM

The only problem with the braid is that you can't be sure to avoid channeling. When the sparge water has an easy path, which I would imagine would be a quick turn towards the centerline just above the braid, you tend to miss a lot of sugar in the lower portion of the cooler furthest away from the braid. I'm not saying you'll absolutely have problems but I would guess at about 60% efficiency.

maltMonkey · 01-24-2008, 05:48 PM

hmmmm.....I hadn't thought of that. I guess if I get a low efficiency I could always add a second or 3rd braid and weave it around the cooler.....

If you're thinking 60% I need to adjust my grain bill, as I think beerTools defaults to 72%. Thanks for the heads up!

**conpewter** · 01-24-2008, 07:21 PM

I'm just starting out AG as well and I'm planning on batch sparging the first few times to get the hang of it, that way I can use the mash tun I just built (with a single stainless steel braid). If i want to go to fly sparging I'll need to make a manifold, probably out of rigid 1/2" copper I'd imagine.

scottfro · 01-24-2008, 07:37 PM

Quote:

Originally Posted by Bobby_M

The only problem with the braid is that you can't be sure to avoid channeling. When the sparge water has an easy path, which I would imagine would be a quick turn towards the centerline just above the braid, you tend to miss a lot of sugar in the lower portion of the cooler furthest away from the braid. I'm not saying you'll absolutely have problems but I would guess at about 60% efficiency.

so does batch sparging lead to less channeling issues then? i have just switched from a false bottom to a stainless braid since upgrading to a 10 gal setup using a keg as my mash tun and i got a pretty low OG (though this could also be due to the mash being too hot (72 C)).