I am new to all grain brewing and am confused as to the length of time to fly sparge. Is there a formula of number quarts of sparge water to minutes of run time?
I think it would be system dependent. Adding the water fast would approach batch sparging. Adding it slow could require a mashout, or you might change the character of your brew.
I don’t think it’s a matter or preference, not that there’s an optimum.
What we’re looking for is overall extraction efficiency with either method, so it’s not so much a matter of time (at first) but keeping tabs of pre-boil gravity with a refractometer and doing some math in regards to overall wort volume. I keep notes as I go and adjust the process as needed.
I fly sparge on a ten gallon system. My run-off is slow enough that it takes about 30 to 40 minutes to collect 11 gallons of wort. I keep about a half-inch of 170F water on top of the grain bed, matching the inflow of hot liquor with the outflow of wort. I stop when I get the appropriate pre-boil amount, so I don’t have to measure the sparge water volume very carefully.
Cutting the grain bed gently with a long bread knife keeps the sparge water from channeling.
If you are Fly sparging (aka: Continues sparging) you are going to be getting the best efficiency out of any other method. Now i can’t give you exact numbers on your efficiency doing it this way as your system is completely different than mine, and i have nothing to base your previous method upon.
Time is also something that changes with every brewer, my guess for average sparging time is around 20-40 minutes between brewers doing 5-10 gallon batches.
I wouldn’t worry much about hitting an exact time, what you need to concern yourself with is:
While you are sparging you are not creating a channel through your grain (like a under grain river of sorts) an easy way to make sure this happens is to keep 1 inch of water above your grain. Adjust sparge water coming in at the same flow rate of your wort going out.
Some brewers like to cut thin paths in the top of there grain to help make sure the water filters through more evenly.
I would recommend raising your mash to 168-170 (its advised that 170+ temps will pull harsh tannins out into your wort) and your sparge water should be the same temperature and water.
adjust the PH of your sparge water also to reduce the leaking of tannins, i use phosphoric acid.
monitor the PH of your run off wort also, this will tell you when you have rinsed your grain thoroughly enough and extracted all you need (hopefully u hit your target volume) I can not think of the PH number that is the stopping point, hopefully another member can answer that.
I hope this info helps you on your all-grain process.
Cheers
My sparging technique is similar to Jeff’s. There is one component that I disagree with, the mash bed cutting.
Those that know me well are aware that I’m a geotechnical and environmental engineer. I’ve had extensive education and training in flow through porous media (soil). The parallel is that a mash bed is porous media too. Penetrating a stable bed of media with something like a knife would actually increase the likelihood of flow short-circuiting, not reduce it. The thing that the cutting would provide is increased permeability through the bed (by the increased short-circuiting). I highly recommend that anyone that performs this misguided technique should try NOT doing that for their next mash. The runoff may be a little slower, but you won’t have to worry about short-circuiting. I don’t know where this wive’s tale came from, but its not doing what you think it is.
PS: Pro brewers don’t do this either. But its probably because in large tuns, there is no way to ‘cut’ the mash. But they also know that its unnecessary.
In any of my experience i have not ruined a batch by cutting my bed of grain. its not something i practice with every batch, but its never created a channel, as long as they are thin cuts.
although your educational expertise indicates this is a “wives tale” i’m going to find out some ways i can practice this on a home brew scale now that is has got me thinking.
Where have you read that no Pro Brewers do this, as there are many brewers out there and everyone seems to have different opinions, even the pros?
I learned that from Jeff (hopfen) who learned it at Sierra Nevada beer camp, so there’s at least one major pro brewer that needs your expertise.
I have found that it helps when there is a lot of fine particulate on the surface of the grain bed.
Commercial mash tuns are going to be a lot deeper, so raking the surface of the mash to disrupt coagulated protein (teig, or top dough) is going to have less effect on the grain bed itself. That being said, in a cooler I wouldn’t go more than a couple inches deep or you could have channeling.
Thank you all for the input. I have a better understanding of how to fly sparge. Brew On!
Personally, I do not touch the grain bed and get consistent 80% efficiency. I used to get closer to 85% until I decided I could trade some efficiency for sparge time. I now fly sparge 10 gallons in about 25 minutes. As stated it’s all about knowing your equipment. I would start slow so you get the hang of adjusting the input versus the output and take it from there when you check your efficiency. As said, try to keep .5"-1" of water above the grain bed.
I could see cutting the grain bed helping get the sparge water through the coagulated protein, but not how it would help prevent channeling. I don’t see how cutting would ruin a beer either. It may just hurt on a few efficiency points.
Dave
Its interesting that you mention SN since the firm I work for is providing engineering services to both the Chico and Asheville facilities. I’m pretty sure they don’t cut or rake the grain bed in a 200 bbl mash tun. They are sort of big. But the description you and others provide, make it clear that the purpose of the cutting is not: “to prevent channeling”, but to improve flow through the bed by disturbing that surface layer. That makes perfect sense.
I mash with RIMS and the flow rate through the bed during mashing is far higher than when I’m running off. I’ve never seen a layer of anything on my mashes. I wonder why regular mashes present this. Do most brewers have this layer on their mash?
Given the real purpose of the cutting, many shallow cuts through the surface of the bed would be most effective.
Shallow being the operative word here? That would definitely make sense.
At least on my system where I’m constantly recirculating the mash, and the last cutting/stirring of the grain bed is probably 15 minutes before I pump clear wort to the kettle, I always see that there is a layer of fine particulate on top of the grain bed. That makes sense to me as the heavier particles may drop out of suspension sooner leaving the finest particles in circulation longer and being the last thing that goes through the grain bed.
I often get a layer of “stuff” on top of the grain bed during the first run using batch sparging too. I have to break it up bit or water will stand on top of the grain even though the first run has stopped. It doesn’t seem to happen as often on the second run.
I had to break the top when I fly sparged also.
Paul
There can be layer that forms on top of the mash called “teig” which is the German word for dough. That stuff is fine and makes a dense almost impermeable layer.
You can read about knifing the mash in Gordon Strong’s article about the homebrewers at SN Beer Camp. He covers what Scott Jennings said on the homebrew scale, and that one of the homebrewers went back and reported an efficiency increase (Jan-Feb 2010 Zymurgy). That rang a bell with me, as one Larry Bell (pun intended) had talked about how one of the mash tuns got higher efficiency as it had knives, the other didn’t back in the later 90s when they had 2 brewhouses in Kalamazoo.
IIRC SN’s 200 barrel Huppmann lauter tun has a mash rake/knives. I know that Bell’s 200 bbl. Huppmann has mash rake/knives. There is also a large toroidal shaped motor on axis under the tun with the shaft leading up to turn the assembly. The blades can rotate on the arm to have cutting action, or if the blades are along the arm they are used to rake the mash out (I would not like to shovel a 200 bbl mash out). There is a good figure on page 332 at the bottom of the page, hope it comes through.
Look at about 5 o’clock and you can see the motor at Bells, behind the SS pipes.
On the homebrew scale, my simple thinking is that knifing also disturbs the bed and helps plug the channels. We do it when the run off starts - if we remember.
I get it consistently for my weizen, which is 60% wheat and single decocted. Not for any of my other beers, but then those don’t have that much wheat and are not decocted.
I get the thin layer on top of my mash, for sure. It is like a thin layer of damp flour. I stir my mash for a good long time at mash in and have always just assumed that it suspended the lightest particulate matter to the top. I have never cut it, because I simply batch sparge (stirring again after adding the sparge water for the second run).
I takes me a minimum of 45 minutes to fly sparge the mash for a 10 gallon batch. I consistently get 90+ efficiency.
I know that people often refer to this Oberteig as “flour”, but it is mostly proteins, polyphenols, beta glucans, lipids and the like that have precipitated out during the mash. Essentially this is your mash break, which is probably a sign of good pH and calcium concentration.
The risk to channeling is probably that it can lead to flow around the outside of the grain bed having less resistance than through the grain bed. That could lead to reduced efficiency and over sparging during a fly sparge.
I’ve cut it before, but always followed that with a second Vorlauf. A good quantity of whole husks should prevent this from being a problem, though, for most mashes.