Strange Brew Day

[MustangCF]

Hey all... just finished cleaning up after my brew day and I'm a bit confused.

I brew all grain and decided to do a smaller batch today (2.4 gallons) of a Scotch Strong Ale. Mashed in at the right temp (finally got a truly accurate thermometer) and volume of water according to Beersmith. Sparged with the right amount of water at the right temp. Collected the expected volume of wort... Everything actually seemed to go quite well.

But when it came down to putting it in my fermenter, I only had about 1.8 gallons, which was disappointing, and when I took the OG reading when it was cooled down, it was a perfect 1.082.

So, what happened? Clearly I had too much boil off, but if I hadn't, my OG would have been too low, yes? Am I just losing efficiency during the mash?

I mean, in the end, I still am gonna have some pretty tasty beer, I think. It just won't be as much as I think. And that's good... but something went very different for me today than the other times I've brewed.

 

[BrewSRQ]

Yea it would appear your boil off is higher than you intended. What are you using to boil? A lower volume requires less flame, so your boil was probably more vigorus if you used the same settings. Since you hit your og with less volume, it would seem that your efficiency is down compared to the recipe stats, which isn't terribly unusual for bigger beers. What was your recipe?

 

[MustangCF]

From Beersmith:

7 lbs Pale Malt (2 Row) US (2.0 SRM)
8.0 oz Munich Malt (9.0 SRM)
4.0 oz Caramel/Crystal Malt -120L (120.0 SRM)
2.6 oz Roasted Barley (300.0 SRM)
4.0 oz Brown Sugar, Dark (50.0 SRM)

0.75 oz Fuggles [4.50 %] - Boil 60.0 min
0.25 oz Fuggles [4.50 %] - Boil 10.0 min

Scottish Ale (Wyeast Labs #1728) [124.21 ml]

Est Original Gravity: 1.082 SG
Est Final Gravity: 1.018 SG
Estimated Alcohol by Vol: 8.5 %
Bitterness: 22.4 IBUs
Est Color: 20.6 SRM

Mashed at 152 for 75 minutes - 2.47 gallons of water at 163.7 (The temp locked right on 152 after a minute or so)
Sparge with 1.93 gallons at 168

Edit: I'm boiling in a large pot I have had for a long time. I think it's too wide and that's causing massive boil off. My next purchase is a better kettle.

 

[gromitdj]

I agree with @BrewSRQ. While 1.084 isn't an extremely high number, larger grain bills will usually result in a diminished efficiency. Did you measure your first runnings and pre-boil gravities? If so, were they in line with what you expected?

 

[MustangCF]

I agree with @BrewSRQ. While 1.084 isn't an extremely high number, larger grain bills will usually result in a diminished efficiency. Did you measure your first runnings and pre-boil gravities? If so, were they in line with what you expected?

I did not check gravities before the boil. I pulled those first runnings and started to caramelize them in a separate pot while I collected the rest of the wort.

I suppose I should have. Logic tells me that those gravities would have been low though, if I boiled off so much and still hit the correct gravity.

So what do people do to counteract this diminished efficiency? More base malt? A longer mash?

 

[kh54s10]

I add just a little more malt. If you are new to BS you will need to adjust your equipment profile, especially boil off rate until you get the volumes you expect.

I know that I need just over 7 gallons to end up with just over 5 in the fermenter so I ignore the sparge amounts BS tells me to use and go by what is in my BK. I sparge with about half what I need to get to preboil, measure the volume again then do a second sparge with just enough to get to my preboil amount.

This makes the mash tun lighter (little water in it) to carry to the compost pile.

OG levels are a little trickier to nail down than wort volumes. But BS needs to have accurate volumes to get the right amount of malts.

 

[gromitdj]

If you know pre-boil volume, post-boil volume, and O.G. you can use a dilution calculator to figure out a reasonably accurate pre-boil gravity. That should be enough to figure out what your mash efficiency is. Next time you brew the same beer, or one of a similar grain bill, use that efficiency when preparing the recipe.

I like to use my refractometer to take gravity readings a couple of times throughout the boil so that I know if my boil off rate is on track.

 

[MustangCF]

If you know pre-boil volume, post-boil volume, and O.G. you can use a dilution calculator to figure out a reasonably accurate pre-boil gravity. That should be enough to figure out what your mash efficiency is. Next time you brew the same beer, or one of a similar grain bill, use that efficiency when preparing the recipe.

I like to use my refractometer to take gravity readings a couple of times throughout the boil so that I know if my boil off rate is on track.

Yeah, a refractometer would be great for this! I'd never thought about checking the whole time I was doing the boil.

And yeah... I'll do the math and change the efficiency. That's a great idea.

Meanwhile, the yeast is chugging away with a nice layer of krausen. So, while I may have less beer than I wanted, I'm excited that what I do have seems like it will turn out just fine.

 

[gromitdj]

If you are using a recipe software, like BeerSmith, you may be able to adjust the efficiency until you get to your calculated Pre-Boil gravity. Since I prefer Beer Tools Pro, I'm not sure if it's possible in BeerSmith. But that's essentially what I have done in the past.

And to me, hitting my expected numbers is more important than hitting an expected volume.

 

[MustangCF]

I

And to me, hitting my expected numbers is more important than hitting an expected volume.

Agreed. I'd like to nail the number and get the volume close, but I'm much happier nailing my OG even if it means less beer.

 

[jddevinn]

Did you leave trub behind in the BK? little things like thermal expansion, water/wort in hoses/false bottoms/pumps, spillage, hop absorption have a larger effect on smaller batches.

 

[MustangCF]

Yeah, I left behind as much trub as I could while getting as much wort as I could. Yeah... I guess the small batch may have also just thrown thigns off.

 

[dwhite60]

Like someone else said, I use a refractometer and check my wort periodically during the boil. This has come in quite helpful a few times.

All the Best,
D. White