Higher ABV than expected

[DecoJuicer]

I brewed my pumpkin ale last night, and used Beersmith to help me do it. Beersmith said that my OG should have been 1.062, but it actually came out 1.074. The only thing that I couldn't put into the program was the pumpkin.

My question is this, would the starches that washed out of the pumpkin in the mini-mash effect the OG? If so, will it is also effect the FG?

Also, how can I figure that out so that I can adjust for it next time? I really didn't want to brew a beer that is almost 8% ABV, but it looks like that's what I did.

Is there a way to look on the nutritional information and figure out what I have going into my brew?

Thanks
Mike

[Cosmic Charlie]

If it added starches only then it wouldn't affect the alcohol content because starches are not fermentable. You would start with a higer OG but end up with a higher FG as well, hopefully hitting your target alcohol level.

Thats my guess at least.

[OrionBrew]

There are too many variables to say for sure that BeerSmith or others can give you 100% accuracy. Then you must factor in your rate of accuracy, including that of your tools.

Put it all together, however, and you are still off your target by a fair margin. I am not skilled enough in the brewing process to give you any hints on where that discrepancy may lie. I can tell you that an 84% accuracy, given common home brewing instrumentation/practices, may be acceptable.

In fact, I was happy if my chemistry labs in college we over 90% accurate. The best I could ever achieve was 94-96 range. I would expect a 10-20% margin of error to be commonplace, if not expected for home brewers.

[Mad Scientist]

Originally posted by OrionBrew
There are too many variables to say for sure that BeerSmith or others can give you 100% accuracy. Then you must factor in your rate of accuracy, including that of your tools.

Put it all together, however, and you are still off your target by a fair margin. I am not skilled enough in the brewing process to give you any hints on where that discrepancy may lie. I can tell you that an 84% accuracy, given common home brewing instrumentation/practices, may be acceptable.

In fact, I was happy if my chemistry labs in college we over 90% accurate. The best I could ever achieve was 94-96 range. I would expect a 10-20% margin of error to be commonplace, if not expected for home brewers.

Please quantify.

[dparsons]

I would think that if you mashed starches (from the pumpkin) you'll get more sugar - as long as you had enough diastatic power to convert them. It depends on how you did your minimash. If this is the case, I'd expect the FG to be different too. Did you do a starch test after mashing?

If you really want to guess, you could assume a weight equivalence between the pumpkin and wet grain. Either that or figure out what is in pumpkin and try to add it to the list used by the software. It can be broken down into starch, protein, fiber, water, minerals, and other stuff just like grain.

[DecoJuicer]

No, I did not do a starch test.

Soooooo, what I am getting from you guys is just, RDWHAHB?

[Otis_The_Drunk]

I mashed the pumpkin along with my grains and it converted pretty good, but if I were to do this recipe again I would use rice hulls.

I got one big gelatinous mess, I barely got enough for the boil but when all was said and done, I ended up with 5 gallons exactly.

OG 1.074 @ 68.7* F

[DecoJuicer]

I used can pumpkin(100% pumpkin, no additives) and I put it into a mesh bag.

I steeped it right along with the grains for 90 minutes. When all was said and done, I had 9 gallons of wort from an original 12 gallons.

Smells pretty good right now.

[Otis_The_Drunk]

I also used used canned pumpkin with no additives.

I put in my strike water and stirred in the pumpkin and added my grain and mashed for 90 mins.

You say you did a partial mash?
Mine was all grian.

[Otis_The_Drunk]

So if I adjust for temp the OG should be around 1.078.
I just transferred to secondary and the Hydrometer reading was 1.018.

So far the Alcohol would be around 7.86% alcohol by volume.

1.078
1.018 -
----------
0.06 x 131 = 7.86% ABV

Now I just racked the beer and it will set in secondary for 2 weeks. The carboy was set into an 18 gallon bucket and surrounded with water and a t-shirt sat over the carboy.
Will take another reading just before bottling.... Once I know if this beer is going to be good or not, then I will post the recipe.

[OrionBrew]

Originally posted by Boerne Brew
Please quantify.


I am basically saying that some deviation from what is expected should be acceptable, but I cant accurately quantify how much should be acceptable or expected. In the end, this may be a personal decision for a homebrewer given experience and equipment, etc.

Some things off the top of my head will influence OG to expected OG, and some examples:

1. Grain quality – did your LBS change malt companies? One malters Vienna may be radically different from anothers. How did weather effect this years grain?

2. Mash quality – how accurate were you at converting the starch. You have to guess this into the formula, see #4.

3. Hydrometer accuracy – I know that some of the glass tubes are remarkably inaccurate at certain levels. Most are created and calibrated at only one temp with one known point.

4. Formula – Which one was used to come up with the expected OG? Were any others used, compared? Does it just use expected medians, and how close were you to these medians? How much information is guessed into the formula?


In other words, DecoJuicer may not be off by as much as he thinks he is, or is supposed to. And even so, the reason may not be anything he, or any of us, can easily identify.


PS my math was wrong, Deco has an 81% "accuracy", not 84. I originally did it backwards, expected 74 and ended with 62.

[Spicoli]

Deco is using Beersmith software which I'm sure he knows his equipments efficiency within a point or two. That is one reason we use such programs. He not off by a point or two he is way above his normal efficiency. The only thing outside of the norm added to the brewing process is the pumpkin. Here is a food chart just scroll down the page. Pumpkin (http://www.ntwrks.com/~mikev/chart1.html)
It shows canned pumpkin to have almost twice the carbs as raw pumpkin at 20 grams per cup. Isn't this just another number for starches and/or sugar that would affect your OG. Anyway just a thought.