was over at a friend’s house today just seeing his brew process and an interesting question came up. we both have fly sparging systems, but we use them slightly differently.
when i sparge, i keep the water level topped up over the grain the whole time. eventually i pretty much drain my entire 15g hlt into my mash, and get my 15 or so gallons in the kettle. when i’m done, the level of the liquid in the mash is still above the grain bed.
when he sparges, he keeps the water level topped up over the grain, until he gets close to his volume. then he lets the wort drain out of the mash/lauter tun, ending up with 15 or so gallons in the kettle, but when he is done, there is no liquid left in the mash.
i’ve been doing it my way as i thought that is how it should be done, and he’s been doing the same thing for the same reason. it seems like there might be some differences in efficiency as well as ph in choosing one of these methods.
does anyone have any info / opinions? i’ve looked in how to brew, and this question seems to not be covered in the fly sparging sections.
Don’t really have an answer but
I do it your way.
Only because I am paranoid about running out of sparge water before
I get my boil volume, so I keep adding water to the HLT just in case.
If I were more sure about how much sparge water I need I might do the opposite.
I generally have drained the tun by the end. I always make up more sparge water than I need, but often have gauged the volume so it ends up essentially dry so I have less to carry to the compost bin.
Same here. Once in a while I’ll come up a little short on volume but my refractometer tells me if I still have sugars in the runoff or if I can just top off with water. But if I need to I still have sparge water hot because I fill my converted keg HLT all the way so I have hot cleaning water.
How do you know how much sparge water you will need?
I have The Home Brewers Companion
and it says "… generaly sparge water will equal about 3/4
to just over the total volume of water necessary for the mash process.
I don’t understand this?
And I know you’re supposed to stop when the gravity gets below
1.008 but how the hell can you check this without a refractometer?
Stop sparging take a sample of wort cool it down and use a hydrometer?
That seems like a real pain , I’ve just been sparging till I get my boil volume
but sometimes I think I might be going to far.
I go for volume and gravity. I generally want to finish with 6 or so gallons in the kettle (5.5-6.0 in the fermenter) so I start with 7.5 or so. Usually I time my boil using my boil off rate so the OG of the beer will be exactly what I desire.
while these are all helpful responses, they aren’t really what i’m looking for. it really just confirms that there isn’t a consensus since everyone here seems to do it either one way or another.
what i’m really trying to figure out is whether there is an effect on ph or efficiency that would make one method more preferable to the other . . . if i had to speculate, i’d say you might get a little bit better efficiency by ending up with a dry mash as you’d be able to leech out a little bit more of the sugars with that last bit of liquid, but that could have other more negative consequences that might offset that method somewhat.
I meant to check what the more technical literature has to say about that. But as I remember it there was no clear statement either. When the grain bed is running “dry” during the lauter it will compact because the water is not able to keep the upper layers afloat anymore. This can affect the run-off rate. But if a brewery chooses to stop lautering before the grain runs dry they end up with a lot of waste water which they need to dispose of and which is an additional cost. As a result I think they might be lautertring until it is dry.
As for your problem, you may have to see for yourself what works better. I don’t see any reason why one or the other approach would be preferable. There should not be differences in pH. While the additional water, that is in the grain when you leave the bed wet, may have a higher pH it is not collected in the boil kettle and therefore not a problem.
Not being a fly sparger myself, I would prefer to run the grain bed dry because I would add just enough sparge water to get to my desired pre boil volume. This keeps me from having to monitor the lauter to determine when to stop.
IMHO it doesn’t really matter. The only issue would be, as Kai pointed out, the grainbed maybe compacted. I fly sparge and I do it both ways, even with my 10 gallon igloo full, and I mean packed with grain.
How to calc your water. The grainbed will retain approximately .1 gallons per pound of grain. As long as you account for this you will be very close in your calculations. preboil volume = mash water added - .1 gallons * pounds of grain + additional water (sparge ) needed.
I am a die-hard fly… Like Mr Fred, I calculate my runnings. Sometimes I can have Brutus run and when everything is dry, I am sitting perfectly at my boil volume. But usually, I leave about half of the mash under water as a practice, as I like this safety measure.
As far as ph goes my friend, this is a recipe issue, not a sparging issue!
I’ve fly sparged both ways, keeping a steady bed of sparge water in and letting it run dry. It seems to work either way but I’ve never really compared efficiencies, etc. I’ve found that letting it run dry is easier because I have a measured amount of sparge water and once it runs through my kettle volume is usually just where I want it.
That being said I’ve been making the transition to batch sparging simply for the time savings of skipping the fly sparge and have had great results with that as well.
If anyone has noticed an efficiency difference with different methods of fly sparging I’d love to hear it. I would think the biggest difference would come from the amount of time you spend doing the fly sparge
When I fly sparge I run it dry EXCEPT the cloudy, chunky final runnings don’t make it into the brew kettle.
I calculate out the estimated final volume of runnings and make sure I leave at least a quart or two in my lauter tun.
So while I’m watching the kettle on the burner for the ever present threat of boilover, the remainders are draining to lighten the load to the compost pile.
My 6 gal bucket with false bottom system retains about .15 gallons per lb of grain. Less if I’m using a lot of flaked grains.
