Target OG

[stuknkrvl]

My buddy and I brewed an IPA today. We made our own recipe using formulas from Ray Daniels' book Designing Great Beers. Our target OG was 1.065. Simple single infusion mash at 150 F for 75 minutes, sparged, eight gallons in the brew kettle at the start of a 95 minute boil. Ended up with a gravity of 1.075.

I know we can add water to dilute it down, but I'm looking for tips on how to hit gravity as planned instead of having to go through the hassle of reheating and adding in water each time.

Thanks!

 

[Rcbandl]

Post boil volume?? Maybe your boil off is more than you factored in.

 

[Gavin C]

Without knowing more it's hard to say. But if you are routinely overshooting gravity and under shooting volume you need to either reduce your grain bill, increase your preboil volumes, or both. With a 95 minute boil you will have boiled of more than had you boiled for 60. That would equate to lower volume and higher OG.

Of course if 90 min boil is desirable then the solution will be one of the three options above. Do you use any notes from prior brews or software to calculate volumes, grain bill, temperatures etc. these are helpful.

 

[stuknkrvl]

This was the first run with this recipe and only our fourth batch. The first two batches we made (a 5 gallon weizen and a 5 gallon RIS) nailed the predicted target OG but came in way under volume - three gallons each. Then next two batches (15 gallon weizen (I know... ambitious) and the 5 gallon IPA) came in on target for volume but both over shot the gravity by 0.010 each batch.

Maybe this is crazy, but could it be that we're boiling without the lid on our brew kettle and losing too much volume to evaporation?

 

[stuknkrvl]

Also, I have been keeping very meticulous notes so if we do something amazing we can make it happen again.

 

[FatDragon]

This was the first run with this recipe and only our fourth batch. The first two batches we made (a 5 gallon weizen and a 5 gallon RIS) nailed the predicted target OG but came in way under volume - three gallons each. Then next two batches (15 gallon weizen (I know... ambitious) and the 5 gallon IPA) came in on target for volume but both over shot the gravity by 0.010 each batch.

Maybe this is crazy, but could it be that we're boiling without the lid on our brew kettle and losing too much volume to evaporation?

You're right to boil with the lid off - keeping it on is bad practice and leads to bad beer thanks to DMS being stuck in the kettle.

It sounds like you're just dialing in your process. If your first couple batches were on the money for OG but low on volume, it means you had an inefficient mash and higher boiloff than you expected. If you're now hitting your volumes and getting higher-than-expected OG's, it means you've figured out your boil-off but now you're mashing much more efficiently, which is generally not a bad thing. Start to adjust your recipes for the higher efficiency (by reducing the grainbill accordingly) and you should start to hit your numbers more consistently. It's always a process, so don't worry if it takes several batches to get there.

And the last possibility to consider is making sure you're reading your volumes and gravities accurately. Don't trust the volume markings on fermenters - check for yourself with known volumes of water (I use a 2-liter pitcher with volume markings) and note the actual levels. Make sure your OG samples are taken from well-mixed wort and read at the right temperatures, with enough volume in the tube and no bubbles buoying the hydrometer. I only say this because the apparent jump in efficiency between your first/second batches and third/fourth batches is around 100%, so it's likely that there were some incorrect numbers somewhere in there, unless you made a huge change between batches two and three, like milling your grains instead of mashing them whole

 

[stuknkrvl]

Right on. I've simply estimated the efficiency at 70%. We'll run an efficiency test on our stuff and see if I don't need to adjust the numbers. Thanks!

 

[eelpout]

Do your meticulous notes include pre boil volume and gravity?

 

[oakbarn]

We use the BrewMath App (Apple IOS) to calculate our final volume and OG. We adjust the Volume early and always have some boiled water to add if we missed the Evaporation Rate. You need good notes on your Evaporation Rate so you know that if you start with 17.6 gallons of Wort, you will end up with 15 Gallons after a 90 minute boil. We use propane and becuase of that, we have a "range" rather than a specific rate as we change the amount of Propane on each boil as we always go full on till Boil then crank it back. It is better to be a little under Volume as it is easy to added boiled Water at the end. We have set it up so that our HLT is at 180 during the Boil. That way we have heated water to add if necessary and cleaning water after the Wort is in the fermenter.

We also re cycle the 180 degree HLT water through the Duda Diesel PLate Chiller for an hour while we are boiling.

The BrewMath App has several very nice features that makes brew day easy. It can do SG Temperature / Dilution/Evaporation correction, Strike Water Temp for Grain Mass, ABV % and Calories (OG to FG). Great little tool that we use every brew seesion. It has lots of calculations hat I do not use, but I am not sure I can brew without it.

 

[stuknkrvl]

eelpout - Preboil volume, yes, but we haven't been checking the gravity until after the boil. Is that helpful?