Need some S.G.'s if you please

[Brew-Happy]

Does anyone have a rough estimate (or even the direct measurement) of the specific gravity of the resultant boil BEFORE adding the water to top off at 5 gallons? Also, can I get your OG after the water has been added?

It shouldn't matter if it is AG or extract. Both would be great.

I am trying to make a spreadsheet calculator to convert all of the volume measurement to weight via the S.G.'s and needed some realistic numbers to judge the accuracy of my calculations.

For the curious, I find specific gravity and weights to be more accurate than eye-balling volumes. I am hoping to have more control of the OG before pitching and not worrying about the resulting volume of beer.

Thanks.

 

[BarleyWater]

Someone other than me will give you some formulas to use, but it is highly dependant on what ingredients you have, and even where they are from. Each ingredient will have a different amount of ppg. And if you are adding top off water, then you aren't AG, and your OG should be realatively constant using malt extract, and after the boil before top off water SG would be a relatively useless number.

Check out BeerSmith, ProMash or BeerTools Pro. You could also check out the recipator, it's free. http://hbd.org/cgi-bin/recipator/recipator

 

[Brew-Happy]

Someone other than me will give you some formulas to use, but it is highly dependant on what ingredients you have, and even where they are from. Each ingredient will have a different amount of ppg. And if you are adding top off water, then you aren't AG, and your OG should be realatively constant using malt extract, and after the boil before top off water SG would be a relatively useless number.

Check out BeerSmith, ProMash or BeerTools Pro. You could also check out the recipator, it's free. http://hbd.org/cgi-bin/recipator/recipator

Good to know about the AG part. Thanks. Obvious noob issue on my part.

I guess I need to elaborate more.

Here are my thoughts: After boiling the grains and all of the extract, the resulting mix will have a specific gravity of its own. So, if I know this SG and its weight(lbs, minus the weight of the carboy), I can calculate its exact volume. Then I can use the target SG for the wort to calculate exactly how many pounds of water I need to add. This would help me to prevent over or under shooting the OG of the wort and not end up with either too much flavor or watered down flavoring.

It might end up that I won't have exactly 5 gallons of wort, but I would have a constant abv and hopefully the wanted flavor and aroma the recipe should produce.

Seems complicated for just a hobby but that is what keeps me up at night

Thanks for the headsup on the software programs, but a tight budget keeps me from purchasing them. Hence the time spent in Excel

 

[FlyingHorse]

I'm not entirely sure I understand your question, but if you want to know the weight of a given volume of wort at a certain SG, it's:

Total weight = gallons of wort x SG x 8.33

So if you have 3 gallons of 1.080 wort, it weighs 3 x 1.080 * 8.33 = 26.99 lb

If you have 5 gallons of wort that weigh 44 lbs, then your gravity is 44/8.33/5 = 1.056

Note that the difference between 1.050 and 1.060 is only going to be ~0.4 lbs at 5 gallons...you're going to need a pretty accurate scale capable of handling these kind of weights if this is how you're going to measure.

EDIT: just read post #3. I think it would be much easier (and at least as accurate) to just do it with volumes, rather than weights. There's no need to "eyeball" it...you can mark your fermenter and measure your additions accurately enough. A pint one way or the other won't matter.

 

[BarleyWater]

I think I see know. It would be best to figure out how to get a specific amount of wort post boil accounting for evaporation losses (usually around 10-15% depending on the weather) so you have a constant post boil volume every time, them use you recipe to get to a post boil SG where you always need to add the same amount of top off water. Measure the gravity and volume of the wort, then determine how much (in volume, not weight) water you need to add (H2O reads about 1.000). 2.5gal of 1.090 wort with 2.5gal of 1.000 water added will come out to 5gal of 1.045 wort.

That said, the gravities will affect you hop utilization greatly, the higher the boil SG, the less you will get from your hops, so that would be my main concern. Different boil gravities will greatly affect your recipe formulation, these are the more important formulas.

To figure out the exact volume, put marks on the side of your carboy in quart increments using a measuring cup. I have never heard of anyone weighing their beer to determine the gravities, seems too complicated.

Try one of the programs I mentioned before. They all have free trials, and it will give you an idea of how the numbers work, before trying to do it on your own.

 

[Brew-Happy]

BarleyWater,

That is exactly what I am thinking. I think

I tend to make things more complicating in the process of simplifying my thought process. I have lost a number of hours of sleep figuring out equations for compound interest and the area of triangle circumscribed by a circle. Tis my life, though it makes my wife really wonder about me.


It may seem complicated up front, but with the use of a set spreadsheet I can do the calculations almost instantly by plugging in the weight and SG.

Plus, I have embedded a graph to plot the SG with time after fermentation has started. That way I can judge when fermentation is done. So this is a multistage sheet that I will be able to use for multiple brews and save the info for later use.

Thanks again.

 

[david_42]

My recommendation is to pre-boil some water and use that as make-up in the fermenter. Trying to use SG is flawed, unless you have absolute assurance your efficiency doesn't vary.