Gravity Question

[mfp03001]

So about a week ago I made NB AG Lefse Blond Kit I've never made one of there kits so I am excited to see how it turns out. I am confused about my final gravity I got. So I am going to show what I got step by step.

The kit has 8.75 lbs. Belgian Pilsner malt (36 GP), 0.25 lbs. Briess Caramel 10 (35GP) and, 1 lb. Soft Blond Candi Sugar (38 GP).

So I did my mash and ended up with 6.4 gallon at BG or 1.038 (after temperature conversion). Which I calculated as 75% efficiency. (36*8.75+35*.25=324, 6.4*38=243, 243/324=.75)

So during the boil I added the pound of Candi. Total gravity points are now 281 (243+38=281). My post boil volume was 4.6 gallons. The gravity that I measured was 1.060 (after temperature conversion). Calculated it should be 1.061 (281/4.6). So that's very close I am happy with that.

Now here is the part I cannot figure out. I added boiled water to bring the volume in my fermenter up to 5.4 gallons. So now my gravity should be 1.052 (281/5.4=52) However, I measured it to be 1.045 or 1.046. I measured it several times at different temperatures once I cooled it in the freezer to 60 degrees so I would not have to use my temperature conversion table. I took one after all the crap had settled in the fermenter (before pinching the yeast of course), and it still came out the same. And I can't figure out why. I know its not a big deal but it was really pissing me off and now that I have so time I though I would share and see if anyone may know why this happened, or if I calculated something wrong or something.

 

[northernlad]

It is very common to have a funky gravity reading after adding water. If you are confident that your OG pre top off is correct, then you post top off should be fine. Plus there are no demerits in homebrew for missing gravity.

 

[mfp03001]

Well not as confident as I was originally lol. The only reading I took more than once was the last one. But I thought the only ones were fine. I was all happy with my 75% I made some adjustments to my mash and lautering and 75% was quite an imporvment for me I was in the high 60's before.

 

[Bigscience]

Was your post boil volume from the kettle or IN the fermentor? If you used a kettle volume, lost some volume doe to hops, transferred to the fermentor without measuring and then topped up with water, you over diluted. Other than hop loss, there is also shrinkage of about 4% to consider.

 

[suprchunk]

Your temperature conversion might be off. Since that is the only thing you changed, never change anything. You converted temperature on everything, except the last measurement. Why did you trust your converting up until that point? Then suddenly didn't trust it enough to keep all the variables the same.

 

[mfp03001]

No the wort was in the fermentor for both those volumes given. I have it marked ever half gallon that's have i estimated my volumes.

I guess I didn't trust it because it was not telling me what i expected it too. All my conversion numbers came from my book How to Brew by John Palmer. Appendix A. I never didn't calculate them out or anything like that.

 

[shortyjacobs]

Usually, water and wort have a tough time mixing, due to different SG, temp, etc. It's no big deal, the yeasties will mix it all up for you, but it's very tough to get a well mixed sample after topping up, which leads to an artifically low (or high) reading. Sounds like you did everything right, I say RDWHAHB.

 

[mfp03001]

Alright, well thanks everyone for your input.