Fly Sparging Question

[dutch101st]

My question is in terms of rate; if I am draining my HLT into my MLT, how much of a rate of drainage will the grain cause?

For example, if I have the ball valve at 1/2 open on the MLT, then will I have the HLT set the same or will I have to set it to a "less open" sort of deal?

 

[menschmaschine]

If they're both the same in terms of valve size and tube diameter, the flow rate should be the roughly the same. You want the flow for both to be the same to maintain the level of water above the grain bed.

 

[iXanadu]

I find that the MLT flows slower than the HLT, and I've always attributed that to grain bed. Getting these right take me quite a while. I concentrate on MLT rate first, shooting for 60-90 minute sparge. I'm adjusting the rate while "clearing" and recycle what I'm catching - it generally takes about a gallon. Once I'm moving wort at x quarts a minute, I start the HLT and adjust to make sure it isn't loosing ground.

 

[LooyvilleLarry]

On my last batch, I opened the MLT about 1/4, then adjusted the HLT, using the MLT sight gauge to keep the water level where I wanted it. 82% efficiency, so maybe I did something right.

 

[The Pol]

I do a 30 minute fly sparge.

I set the flow on my MLT, then match it with the HLT by monitoring the fluid level in the MLT for about 5 minutes or so. They are actually pretty easy to match.

 

[ajf]

My HLT starts flowing fast, but then slows down as the level drops. The MLT starts flowing slow, but speeds up as the viscosity of the wort drops. A quick adjustment every 15 - 20 minutes keeps things in balance.

-a.

 

[koolmonk66]

Everyone's system is different. Shoot for one pint per minute into the boil pot, maximum while maintaining 1-2 inches of water above the grain. Don't let the grain go dry! Like the guy above, 60-90 minutes (for ~7.5 gal). This will help your efficiency, too. I've proved it to myself a few times.

 

[The Pol]

FWIW, it only takes me 30 minutes to fly sparge 7.8 gallons, and I run my MLT dry at the end of the sparge. My eff. runs 82-83% all the time.

 

[beerthirty]

If you are using a 2 pump system open the MLT all the way to prevent cavitation in the pump and adjust the output into the BK. Then match it with the sparge pump output valve leaving the hlt valve open all the way to prevent cavitation to that pump. You never want to restrict the inlet side of a pump no matter how many pumps you are running, particularly if you are pumping hot liquid. The hotter the liquid and the less pressure at the impeller the bigger chance you have of cavitaion or promoting intake air leaks. Cavitation will collapse when the pump is turned off, but intake airleaks require the pump housing to be flooded again. This can be hard to do without a bypass to vent the air.