Boil off question

[bhop2112]

Hi everyone,

Yesterday was my first brew day and things went pretty well overall. However, I do think that I greatly underestimated the volume I would boil off.

I did a partial mash kit from AHS and I was shooting for an OG of 1.058. I did a full boil starting with a total volume of 6 gallons and boiled for 60 minutes. I didn't think to take note of my final volume, but my OG measured 1.076. The beer has been in the fermenter for around 12 hours and I have seen a bubble or two in the airlock this morning.

At the time, it didn't occur to me to check my final volume ( ), but thinking back on it this morning, I'm pretty sure that it was a fair amount less than 5 gallons.

So, I have two questions. First, any ideas why I boiled off so much more than I was expecting? I'm guessing that I may have just had my flame too high. That coupled with the fact that my 38qt kettle is pretty wide and provides more surface area may have been it, but some more opinions would be welcome.

Second, what should I do about it now? Forget about it and just let it finish out? I realize I'll probably end up with a higher FG that I wanted, plus maybe a sweeter beer in the end. Open up the fermenter and top it off now? Top it off at bottling time?

Thanks in advance for any feedback.

Oh, and I also just wanted to say that this forum is awesome. I've been reading posts for weeks now in preparation for my first brew day and I have learned a ton.



Brett

 

[Yooper]

I'd add some boiled and cooled water to make up the volume.

Do you have any lines on your fermenter to guestimate the volume? If you have 4.5 gallons now at 1.076, adding one gallon of water will give you an OG of 1.062 for 5.5 gallons.

I'd add the water until I was at 5 gallons or at the OG the recipe called for.

Boil off is tricky, because everybody's system is different. Also, most people will boil off far more in the winter when the weather is drier, than in the summer when it's humid. The brewers in Arizonia brew off more more than the guys in Florida, because of the humidity!

I start with 6.5 gallons - 7 gallons in my keggle system, but on my tall thin turkey fryer I start with 6.25 gallons because of the more narrow opening on that pot.

Once you know how much you boil off, it gets easier! I'd suggest marking your kettle (or your spoon) at each gallon/half gallon so you can see at a glance how much you have, and mark the fermenter too. Check the SG of the cooled wort in the kettle, so you can see if you need to do anything (like add water) before putting it in the fermenter.

 

[bhop2112]

Wow, thanks Yooper for such a quick and detailed response! :rockin:

I'm boiling the water to top it off now.

After I add the cooled water, I'll want to get another SG reading, but it seems like I will need to stir and make sure the water is mixed in well to get an accurate reading. Should I be concerned with oxygenation or disturbing the fermentation in any way during this operation? Obviously, I'll make sure the spoon and thief are santized.

Thanks again!

Brett

 

[bhop2112]

OK, just finished topping off and my SG is now at 1.059. That's better

Thanks again!