Fly Sparging and Grain:Water Mash Ratio

[taylorjohn11892]

Help!

I am working with an all grain 10g batch keggle system using the "Ultimate Sparge Arm". I have only brewed simple IPAs or APAs.

My issue is that I am falling roughly .010 - .020 points below my expected OG every time I brew (only about 4 total so far).


Let me explain my mash procedures:

1. Dough in and calculate water to grist ratio by including the water below the false bottom... Is this correct??

2. After mash rest, I vorlauf until it runs clear. Then I drain into boil kettle until about 1" of water is above the grain bed.

3. Start sparge arm and water @ 170F to maintain the inch of water on top of the grain bed while pumping into boil kettle. Total amt of time sparging roughly 30-45 min.

4. Sparge until my target BK volume is reached (11.5 g) with a little bit of water left in the MT. (its hard to estimate how much water is in MT.


Can someone please enlighten me on how to calculate the water to grist ratio (do I include water below the false bottom)??

Also, can someone please teach me in words how I should be fly sparging to get my efficiency up?? From what I understand I should be in the 70-80% range and right now I am sitting at 60-65%!!


Thanks!!!
TS

 

[dyqik]

You shouldn't include the water below the false bottom in the water to grist ratio.

On efficiency, you need to know a few things to identify your problem. You should measure the conversion efficiency to make sure that your mash is actually gelatinizing the starch to get it into solution, and then converting that starch to sugars. That will require measuring the first runnings gravity and doing an iodine test (you could dispense with the iodine test). You should probably also measure mash pH to be sure that that isn't limiting your conversion efficiency.

Then you should measure the final runnings gravity, and measure your lauter efficiency.

Both of these measurements are laid out in the Braukaiser wiki at http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency

 

[taylorjohn11892]

So next time I will measure the first runnings gravity - after vorlauf or before?? What should my gravity look like at that point because obviously it will be more dense than what is in the BK after sparge.

What is a good water to grist ratio and does that number affect efficiency?

 

[dyqik]

The first runnings gravity should be the same before and after vorlaufing.

The grain to water ratio does affect efficiency, but not that strongly.

In both cases, see the Braukaiser link for details.

 

[Kjay]

What is your a average water to grain ratio? A typical rule of thumb for this is 1.5 qts/lb malt (this ratio is can be between 1.25-2 as required) . So for a ten gallon with 20 lbs of malt you would have 30 qts of water or 7.5 gallons in your mash tun (20*1.5=30). This may or may not help with your calcs pre mash depending if you are doing this already.

I use straight up Costco spring (clear green bottle don't know if you have the same in the states) water as my water source usually with no chemistry interventions resulting with overshooting my gravity.

Also sparging I use 4-6 mins per gallon for my fly sparge. I tend to shoot for 4 minutes because sparging for over an hour sucks.

Let us know what you try to fix your issue and their results.

 

[doug293cz]

You shouldn't include the water below the false bottom in the water to grist ratio.

On efficiency, you need to know a few things to identify your problem. You should measure the conversion efficiency to make sure that your mash is actually gelatinizing the starch to get it into solution, and then converting that starch to sugars. That will require measuring the first runnings gravity and doing an iodine test (you could dispense with the iodine test). You should probably also measure mash pH to be sure that that isn't limiting your conversion efficiency.

Then you should measure the final runnings gravity, and measure your lauter efficiency.

Both of these measurements are laid out in the Braukaiser wiki at http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency

What he said (mostly.) I recommend skipping the iodine test, especially if you are measuring after vorlauf (any remaining starch is likely to be trapped in the center of the grits, and not in the wort.)

The first runnings gravity should be the same before and after vorlaufing.

The grain to water ratio does affect efficiency, but not that strongly.

In both cases, see the Braukaiser link for details.

SG could be a little higher after vorlaufing. The wort under the FB could be a bit lower since you can't really stir down there, so the only way sugar gets into that volume is by diffusion (unless you recirculate your mash.) Thus, I recommend taking the first runnings SG after the vorlauf.

If your conversion efficiency is less than about 95%, you should see if you can reduce your crush size without getting a stuck sparge, as finer grits convert faster, and often more completely. Crush as fine as your system will let you. Also, make sure your mash pH (measure after 15 - 20 minutes, with sample at room temp) is in the range 5.3 to 5.7 to get best conversion. Learn to use BrunWater or EZWater to predict your mash pH, and adjust your water chemistry as needed. Compare your predicted to actual pH, use that to adjust your water additions for future brews. Don't try to chase the pH in an ongoing mash.

If your conversion efficiency is still low after doing everything above, then try mashing longer, or you could try that first.

If your conversion efficiency is good, then the problem is with lauter efficiency. The first thing to try with the lauter is to slow down the sparge. The biggest detractor with fly sparging is the sparge water channeling thru the grain bed, bypassing most of the grain.

Brew on

 

[taylorjohn11892]

In my water to grist calculation here is how I am doing it:

20.37 lbs of total grain
1.5 qts / lb

30.55 qts = 7.63 g of water in the mash tun

Do I subtract the water lost in spent grain (3g) and water lost under the false bottom (2.5g) in order to determine a perfect volume in HLT?

In doing this I'm trying to suck my MT dry when transferring into BK. Please help a brotha ouT!!!!

 

[doug293cz]

If you wish to leave your MLT "dry" after run-off, the equation for your total brewing water is:

Total_Water = Target_Pre-Boil_Vol + (Grain_Wt * Grain_Absorption_Rate) + MLT_Undrainable_Vol​

Your sparge volume is then just Total_Water - Strike_Volume. Note that volume under a false bottom is not the same as undrainable volume. Volume under the FB will make your mash thicker than expected from a simple qt/lb ratio. To get the target thickness, your strike water should be qt/lb * grain_wt + volume_under_FB.

Brew on

 

[kh54s10]

I do batch sparge so take what I say cautiously. But, I think you are over complicating things. Mash with between 1.25 and 1.5 quarts per pound of grain. If you have a lot of grain you might have to mash with more water. Do the mash. Vorlauf and start draining while adding water to the sparge at the same rate as the drain to keep about an inch above the grain. You then collect the wort until: 1) you have enough for your preboil amount. Or 2) you have dropped to your preboil gravity. If the two don't coincide you need to find out why. For instance if your gravity is too low and you have not gotten to your preboil amount, your conversion is bad or your crush is bad. If your gravity is high and you already have your preboil amount your efficiency is better than the recipe wanted so you could alter the expected efficiency in the recipe app to use less grain.

I think that you really want more sparge water heated in the HLT than you think you will use. I also think that it is not important other than having water and grain weight in your mash tun, whether there is water left or not as long as you are getting the right volume and preboil gravity. I batch sparge, so I aim to drain all the water.

 

[taylorjohn11892]

Okay so I'm going to use iodine to test my conversion efficiency,and see if my mash PH is something I should be fiddling with. I'm also going to sparge slower, I've been averaging around 30 min so maybe 60 min will help.

I'm going to mash with a grist ratio of 1.5q/lb with 20 lbs of grain to give me 7.5g in the MT (disregard water under false bottom completely???)

I'm gonna have 10g in the HLT (more than probably needed) and sparge until my BK reaches 12.5g. Do I leave a remainder of the wort under the false bottom before reaching desired BK volume????

Rest at 150F for 60-90 min

How does this mash plan sound for your average Pale Ale?

Thanks for the help folks

 

[doug293cz]

Sounds like a plan. Yes, normally when fly sparging you leave the diluted wort in the MLT once you have reached your target pre-boil volume. But, there are some who try to end up with a "dry" MLT after a fly sparge. Fly sparging is exceedingly difficult to mathematically model (simulate) so I can't say which method results in higher lauter efficiency. I suggest you stick with the first, most common method until you get more experience.

Brew on