Author Topic: Est original gravity vs boil volume, boil volume vs boil time  (Read 4274 times)

Offline tak

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Est original gravity vs boil volume, boil volume vs boil time
« on: August 11, 2015, 09:59:40 PM »
Hi, I have 2 questions :

First, I'm wondering why the est original gravity doesn't change as I'm adding water. IE : If I add losses for trub, the software adds water to compensate, but doesn't adjust the est OG. Technically, the more losses I have, the more water I need to add to reach my volume, and to keep the same OG, I would have to add some grain, but beersmith never changes that number regardless of what I change in the equipment profile.

Also, How can I make it so that when I change the boil time on the recipe page, my boil volume changes as well?


Thanks!

JP

Offline Oginme

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Re: Est original gravity vs boil volume, boil volume vs boil time
« Reply #1 on: August 12, 2015, 05:52:43 AM »
BeerSmith uses the brew house efficiency as a constant for calculations.  So when you add water to the process or increase your boil time, BeerSmith changes your mash efficiency to compensate for the needed sugar content.  When you key in the changes, note the difference in Mash Efficiency.

I've found my Mash Efficiency to be incredibly consistent, while my brewhouse efficiency varies based upon the amount of hops I add and non-barley adjuncts used.  As such, I design for mmy given mash efficiency and adjust the brewhouse efficiency to maintain my target mash efficiency based upon my known history.
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Offline brewfun

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Re: Est original gravity vs boil volume, boil volume vs boil time
« Reply #2 on: August 12, 2015, 06:40:51 AM »
First, I'm wondering why the est original gravity doesn't change as I'm adding water. ...but beersmith never changes that number regardless of what I change in the equipment profile.

You're confusing mash efficiency and brewhouse efficiency. This is actually the correct way for efficiency to be calculated when the Brewhouse Efficiency is the determining factor. What you're describing is based on mash efficiency being constant.

Brewhouse Efficiency is the percentage of sugar that makes it to the fermenter. This means that if you have 1 gallon of trub loss, and 4 gallons make it to the fermenter, you have 80% of the sugars extracted getting to the fermenter. Thus, 80% Brewhouse Efficiency is the highest possible number.

If you know you'll get 70% of the total available sugar from the grain, this reduces your brewhouse efficiency from the maximum illustrated above. If you measure your wort at the higher gravity with more volume, then the ONLY possible place to gain that sugar is with better mash efficiency.

If you're more comfortable making your batch size measurements in the kettle, then set trub loss to zero to make the Brewhouse Efficiency the same as Mash Efficiency.

Quote
Also, How can I make it so that when I change the boil time on the recipe page, my boil volume changes as well?

In the recipe, open the equipment profile using the small checkmark box next to the profile name. Make sure the boxes "Calculate Boil Vol..." and "Use boiloff as..." boxes are checked.
Beer Appreciation is the space between pints.

Offline tak

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Re: Est original gravity vs boil volume, boil volume vs boil time
« Reply #3 on: August 14, 2015, 07:43:00 PM »
There is no "use boilof as" checkbox... I'm using the apple version perhaps that is why.

I get the brewhouse efficiency thing... basically for a constant water quantity, the efficiency will dictate how much grain you need to put to achieve a certain OG for a given volume (accounting for losses etc.) I'm trying to follow a recipe and can't seem to wrap my head on how to adjust it since it seems like my evaporation rate and losses are much bigger than the ones in the recipe. Recipe calls for 23 L preboil to achieve a 20 L batch boiling for 90 minutes  :o where my numbers are more around 34 L preboil for 20 L batch lol. Hence it throws off all the ingredients numbers.... Or should it ?

Edit : tinkering with numbers I've estimated that the recipe uses a mash efficiency of 83 percent (where I'm more along the 75 % mark)... and obviously they must have a weird way of calculating boiloff
« Last Edit: August 14, 2015, 07:48:54 PM by tak »

Offline brewfun

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Re: Est original gravity vs boil volume, boil volume vs boil time
« Reply #4 on: August 14, 2015, 08:10:10 PM »
There is no "use boilof as" checkbox... I'm using the apple version perhaps that is why.

The box is in the equipment profile. The full name of the check box is, "Use boil off as hourly rate" and it's located between the boiloff and total boil off fields.

Quote
I'm trying to follow a recipe and can't seem to wrap my head on how to adjust it since it seems like my evaporation rate and losses are much bigger than the ones in the recipe. Recipe calls for 23 L preboil to achieve a 20 L batch boiling for 90 minutes  :o where my numbers are more around 34 L preboil for 20 L batch lol. Hence it throws off all the ingredients numbers.... Or should it ?

The batch size (what gets into the fermenter) and starting gravity should be the same between the two recipes. You can choose whether your batch size is based on kettle volume or fermenter volume. If you zero out the loss to Trub & Chiller, then you're just working from kettle volume.

If you enter the recipe with their equipment profile, their numbers and ingredient amounts should match up. Then, you want to use the "scale recipe" function to adjust the ingredients to match your equipment profile. BeerSmith will automatically calculate the recipe based on your volumes and efficiency.

Quote
Edit : tinkering with numbers I've estimated that the recipe uses a mash efficiency of 83 percent (where I'm more along the 75 % mark)... and obviously they must have a weird way of calculating boiloff

Efficiency and boiloff are not related. Boiloff is the concentration of wort during the boil. Your system may have more boiloff, but this is how high you turn up the burner, not how much you extract from the grain. At the end of the day, the batch volume and starting gravity should match.
Beer Appreciation is the space between pints.

 

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