Batch Sparge - Efficiency Slip - Let's Talk

Everyone knows I'm a batch sparge advocate and I get pretty good efficiency. That's not in question today.

I'll start by saying this is my first batch where I went sub 80% brewhouse. I will chalk up some of that to a rather large leaf hop bill and the continued loss of wort in my CFC, March pump, and 1/2" hoses. However, I still only hit 82% extract efficiency out of the MLT while I had it set to 88% in BTP. Yeah, I missed my OG.

There are two things at play here and I'm pissed that they both happened on the same batch.

Higher intended OG = Lower efficiency:
I think most of us agree that as your intended OG goes up, your efficiency goes down. It's a direct result of the reduced grain to sparge water ratio. I was shooting for 1.068 while most of my 88-92% efficiencies were scored on 1.050ish beers. Ok, got me there.

Lower sparge water temp = Lower efficiency:
It was the coldest my garage has ever been during brewing.. 45F. I had the door cracked open to avoid asphyxiation too. I heated the sparge up to 185F but by the time I infused, the mash settled to 159F. DOH! Then in order to get moving on the boil, I put my second batch of sparge water into a bucket. It had really dropped in temp by the time I mixed it in. This time the mash temp equilized all the way down at 154F, nowhere near the optimum 169F.

So, now I really have no idea which factored in the most to the lowered efficiency. I guess I'll have to plan another bigger beer just to test it out. Even at 1.061, it's the biggest beer I've made. I just have to wonder where the point of diminishing returns is. Throwing in a pound or two of DME might be cheaper than 10lbs of 2-row.

Afterthought.. One way to avoid leaving wort in the chiller, pump and tubing is to have a gallon of water in a sanitized container and just as the last wort is leaving the kettle, dump the water in. It will help the pump maintain prime while it pushes the last of the wort into the fermenter. Stop pumping just as the water reaches the end of the line. (see how posting helps the thought process?)

The low sparge water temp has bit me in the ass this winter. If you don't have something insulated to store the sparge water in, heat it up to almost boiling. If it's still to hot when you go to use it, throw in some cold water or ice to hit your target.

That's a good suggestion. Once I finally complete my single tier setup, it won't even be problem anymore but that should definitely help people that use a single burner and temporarily store sparge water.

Bobby_M said:

Higher intended OG = Lower efficiency:

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I learned it same way you did. I was foreseeing it but did not think the extent of the effect. Ended up with 1.058 instead of 1.068. I think the way to attack it is to increase amount of sparge water and correspondingly boil time.

I think it's probably mostly due to undersparging since you had a larger grain bill. Lower temp on the sparge water probably didn't help either, but my guess is if you had sparged with an extra gallon or so and boiled that down, you wouldn't be disappointed.

Afterthought.. One way to avoid leaving wort in the chiller, pump and tubing is to have a gallon of water in a sanitized container and just as the last wort is leaving the kettle, dump the water in. It will help the pump maintain prime while it pushes the last of the wort into the fermenter. Stop pumping just as the water reaches the end of the line. (see how posting helps the thought process?)

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That's some good thinking there.

One way to offset some of the efficiency loss is to sparge more and boil down. The rule of thumb I use is .5 gal/lb for sparge water. With a 30lb grain bill that means 15 gallons of sparge water.

I'll break up the wort into two kettles and start the boil. Once the volume has gone down in the main kettle, I'll add the wort from the second smaller kettle back in. It does make for a longer day, but my efficiency doesn't suffer as much. If I normally get 87% on a fly sparge 20lb grain bill, I'll set the recipe down to 75% for a 30lb grain bill. It's only about 3 or 4 pounds more grain at that point so should only be one or two more gallons of sparge liquor. I'll come alot closer to hitting my OG, though I won't hit the 87% I would on a smaller beer. But 75% of a large beer is pretty good.

I think increased boildown also hits a wall because time and gas is not free. I usually boil 70 minutes but did a 90 minute on this one. I think I'll set the efficiency for 70% next time and add the $5 worth of grain next time.

My larger grain bills see a lower efficiency as well.

One thing I did (by accident) was to let the mash sit for 90 minutes one time. Same exact 1.057 recipe as I'd done before, but I unexpectedly picked up 5 gravity points.

Sure enough, my next batch (different beer) I did an 80 minute mash, and again overshot my gravity (compared to one of my prior standard recipes).

Jamil advocates a longer (90 minute) mash if you're mashing at lower (borderline) temperatures to insure complete conversion. Perhaps a higher grain bill also benefits from a longer mash time.

It would only cost you 20-30 minutes to test it next time.

Here's what I do: using my normal mash setup (60 min mash, target 6.5 gal preboil, 60 min boil gets down to 5.5 gal in fermenter), I get my target efficiency for any grain bill 10# or less.

For every pound over 10, up to 15, I subtract 1 point of efficiency.
Over 15 lbs, I up the preboil to 7 gal, do a 90-minute boil, and knock off another 2 points of efficency for each pound over 15.

This seems to work pretty well.

BierMuncher said:

My larger grain bills see a lower efficiency as well.

One thing I did (by accident) was to let the mash sit for 90 minutes one time. Same exact 1.057 recipe as I'd done before, but I unexpectedly picked up 5 gravity points.

Sure enough, my next batch (different beer) I did an 80 minute mash, and again overshot my gravity (compared to one of my prior standard recipes).

Jamil advocates a longer (90 minute) mash if you're mashing at lower (borderline) temperatures to insure complete conversion. Perhaps a higher grain bill also benefits from a longer mash time.

It would only cost you 20-30 minutes to test it next time.

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I recently started doing 75 minute mashes across the board. It's only been 4 brews, but I hit or exceeded my target on every brew so far. 1.090(target 1.088), 1.060 (target 1.054), 1.060 and 1.058 (target 1.056).

Then in order to get moving on the boil, I put my second batch of sparge water into a bucket. It had really dropped in temp by the time I mixed it in.
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I have been running from the keggle/HLT straight in to the mash tun after my first runnings have been collected in buckets or in my not in use HLT (spare 10 gallon cooler).

I agree that sparge temperature and volume are the big culprits here. When you are talking about pushing efficiency from the low 80s to the high 80s (or visa versa), tiny changes in the process make big differences.


TL

I do a long mash-in. It's easy for me since I'm using the steam infusion system. I crush the day before brewday and dump the grains in the cooler. On brew day I pour in the mash water and start heating it up with the steam. At about 115F I shut everything off and leave the cooler to do all of my morning stuff: shower, coffee, cigarette, etc. My first 10 gallon batch hit 85% at 1.051. It spent over an hour and a half just soaking in the warm water. With a really good crush, this probably wouldn't help much, but my with my corona, I'm pretty convinced this is the only reason my efficiency is as good as it is.

I think in this instance (maybe, but read on) FLY sparging would have helped you!





Maybe, maybe not....



Seems to regulate temps well...

Spyk'd said:

I think in this instance (maybe, but read on) FLY sparging would have helped you!





Maybe, maybe not....



Seems to regulate temps well...

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Only if he could keep the sparge water at temp. but then agin, if he could have done that then he may not have had this problem in the first place.

Yeah, If it was a temp issue, letting the sparge water sit around for an hour would have made it worse. If it's just a grain bill issue, well I'll just have to account for that and know that I can't really do 10 gallons of beer over 1.065 in my 48qt cooler because the tun was pretty maxed out at 24 lbs. I hope to be using my 1/2BBL MLT by the next batch so it's kinda moot.

The more I think about it, I think it was probably mostly sparge temp. I've hit 88-92% efficiency on beers ranging from 1.050 to 1.059.

On the batch I hit 1.059 on, it was actually 88% brewhouse and I measured and noted my equalized sparge temps at 163 and 169F respectively. It doesn't seem like a coincidence.