Kolsch Final Runnings SG Too Low – What am I Missing?

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philm63

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I know I’m missing something – likely something obvious – in my setup. I do 5-gallon batches using Beersmith2, build my water from RO, use a 3-vessel electric HERMS with 10-gallon Boilermaker G2’s, and ferment in a 7-gallon SSB unitank. I’ve created equipment profiles for each style I brew – mostly IPAs, porters, stouts, and one of my favorites; Kolsch. These profiles revolve around the amount of grain and hops and so far, they’ve worked perfectly for all except the Kolsch.

With all the other styles I get the final runnings from the mash down to around 1.015 SG to 1.010 SG by the time I hit my volume and gravity targets in the kettle. But by the time I hit my targets with the Kolsch, the final runnings are down to 1.002 or 1.001 SG.

I like to have between 6.5 and 7 gallons available for the fermenter as the chilling coil sits up pretty high in the SSB unitank (wish they’d make a coil that sits lower in the tank). I want the fermenter just about full to ensure I can get good temperature control while leaving some headspace for krausen. I don’t mind a bit of waste at the end so I configure my BS2 equipment profiles to be 6.5- or 7-gallon batch sizes and account for system losses due to HERMS coil, lines, pump, etc.

One of the biggest differences in all these brews is the size of the grain bill. Most are in the 13-15 Lbs range and for these, I have no problems with the gravity of my final runnings – never goes below 1.010 SG. In contrast, the Kolsch uses around 10 Lbs of grain so I think the problem stems from the fact I’m trying to pull the same total volume into the kettle as my other brews but with much less grain hence the low SG final runnings.

I’ve set my profiles up using the same general logic and all work fine but the Kolsch profile. What am I missing here?
 
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philm63

philm63

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I'd thought of that but I also see that it just pushes the OG number way up. That's where I'm getting stuck - what could be wrong with the setup (equipment profile, or...?) that the recipe in BS2 tells me I'm going to get a 1.048 OG as desired but my final runnings are way low? Just for this one style, too.

EDIT - Is it possible BS2 is not handling the calculations correctly for batches using such a small grain bill?
E2 - Sounds like this might best be addressed by the BS forum.
 
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hottpeper13

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My Kolsch starts at 1.044 (11-p*) and I mostly do a no sparge BIAB. Sounds like you could still do a step mash recirc with full volume. I don't use programs just a calculator, pencil and the original back button,but I would think 7.5 gal would do it and fit your system.
 

JohnDBrewer

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Are you saving an old equipment profile with your Kolsch? On BS if you are taking your last recipe and just "saving as" (say v.6) you are saving whatever v.5s equipment profile actual was. If you have made changes to your "master" equipment profile after v5 it will not update old recipes brewed previous to this change. If you are just saving an old recipe version to a new version you are carrying forward an old equipment profile. Does that make sense and could that be your issue?
 

Spartan1979

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There's going to be less sugar in the mash with less malt so you're going to see lower numbers. If you're hitting your target pre boil gravity then you're good. You may want to stop sparging earlier as a gravity of less than 1.010 can add tannins to your wort. If you don't have enough volume, add water.
 
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philm63

philm63

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Are you saving an old equipment profile with your Kolsch?
That's a good point but in my case, I upgrade the profile to correct for issues during a brew and rename that new profile, and am sure to include that new profile when brewing that beer again to ensure my changes are in there. My old versions of this brew still have their respective "old" profiles in them so I can always go back and see what happened with each iteration to make sure I am on track.

There's going to be less sugar in the mash with less malt so you're going to see lower numbers....
You've hit on something here but in a way I didn't see before - less sugar in the mash. I understand my extraction efficiencies pretty well and have also adjusted my brewhouse efficiencies for each profile to track the size of the grain bill noting, from experience, that my BHE is high (up to 82%) with lighter grain bills and low (down to 76%) with heavier grain bills... wait, maybe that's it! Cripes! Maybe I'm reaching a bit too high for my BHE on this style.

Thoughts?
 

doug293cz

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I'd try mashing much thinner and sparging less, to get the same pre-boil volume. This should bring up the ending SG of the sparge runnings. Target a mash thickness of 2.5 - 2.9 qt/lb, rather than 1.25 - 1.5 qt/lb.

You could also go with a less vigorous boil, for less boil-off, and reduce your pre-boil volume target.

Brew on :mug:
 
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philm63

philm63

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So then would it be safe to say with a smaller grain bill, one could benefit from a thinner mash?

I'd been setting all my styles to a 1.5 qt/Lb ratio.
 

ScrewyBrewer

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@philm63 enzymes in a thin mash more efficiently convert starches into sugars than in a thicker mash. And that increase in the number of sugars converted from starches in the mash, will boost conversion efficiency.

Did you know that ezRecipe Design saves the equipment profile used to brew each recipe along with the recipe information?
 
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doug293cz

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@philm63 enzymes in a thin mash more efficiently convert starches into sugars than in a thicker mash. And that an increase in the number of sugars converted from starches in the mash, will boost conversion efficiency.
I would phrase this as "the rate of conversion is faster in thinner mashes, due to faster gelatinization and/or higher mobility of the enzymes." This means a thinner mash will reach 100% conversion sooner than a thicker mash (all else being equal.) Once you reach 100% conversion, the SG of the wort will not increase with a longer mash, but it will likely become more fermentable. If your thicker mash was not already reaching 100% conversion, then a thinner mash, done at the same temp, for the same amount of time, will give you more conversion (higher conversion efficiency.)

Brew on :mug:
 
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