I need larger preboil volume. Do I use more mash water or sparse water? Both?

I brewed yesterday and had a mash with 5 gallons and a batch sparge with 4.5 gallons.  My goal was to have 7 gallons preboil but I ended up with about 6.5 and barely 5 gallons into the fermenter.  How do I go about correcting this?

EDIT: should be sparge in the title; thanks, autocorrect.

How much grain (lbs.) in the mash?

It can go into either I would think if it’s not a huge grist. Try to balance it out for close to equal runnings for the best results, or so I’ve heard and had success with

Something does not sound quite correct.  I made a batch today with 12lbs of malt, 3.75 gallons of strike liquor, and 5 gallons of sparge liquor (continuous sparge).  I collected 7.25 gallons of runoff, which is what I calculated.

14.5# total

Increase your total amount of water…continue sparging until you get the desired kettle fill…

I would say it’s best to add to sparge. I typically mash at 1.7 qt\lb, add about 1.5 gallons before first run off, and batch sparge with whatever is needed to hit my preboil. This will range greatly depending on the amount of grain. If the amount of sparge water is low (<2 gallons), I will add it all before runoff.

In batch sparging, the runoff from the mash should be about the same as the sparge to maximize efficiency. Based on 9.5 gallons in and 6.5 gallons out, your mash should be 6.25 gallons and your sparge 3.25 gallons.

It was an IPA with five ounces of kettle hops.  Maybe this had a factor.

After loads of batches, I think this is an unrealistic wives tail type rule. I have had better luck mashing at my preferred thickness, thinning a touch before run off, and sparging with whatever amount is needed.

The amount of kettle hops should not have been a factor with respect to runoff volume.  You should have collected more than 6.5 gallons of runoff with that much brewing liquor.  A pound of grain absorbs approximately 0.125 gallons of hot liquor.  Fourteen and half pounds of malt would hold 14.5 x 0.125 = ~1.825 gallons of hot liquor.  With 9.5 gallons in, you should have collected over seven and a half gallons of runoff (9.5 - 1.825 = 7.675).  You are clearly leaving runoff in the tun.  Are able to post a photo of your tun?

Doesn’t really matter all that much.  As long as they’re within a gal. or so, no big deal.

Here they were outside the 1 gallon. Agreed that +/-10% does not matter from ideal 50:50 ratio.

Not a wives tale but chemical engineering.

For me it doesn’t matter. I get conversion close to what Kai’s table says, and my overall mash efficiency hasn’t changed since I stopped caring about the runnings being equal.

I’ve been pushing the mash runoff to about a gallon over sparge runoff for a while. I like the efficiency bump the thinner mash ratio gives me .