Oops, Boil Volume Too High

[GHBWNY]

I *forgot*:smack: that I split off 1 gal worth of ingredients for a 5.5 gal batch with my s-i-l. Consequently, with a 6.5 pre-boil vol plus sparge, I have about 7 gal of wort boiling for what is going to be a 4.5 gal batch. Is it better to let it boil down before adding hops? Thanks.

 

[Callacave]

Yup. Boil that sucker down. A longer boil can at times be beneficial. Add your hops when your ready and start your 60 min boil.

 

[kh54s10]

Boiling it down is the choice - or ending up with more beer. But if I understand, it would be a weaker, thinner beer that way.

 

[MagicMatt]

I second (third?) the remarks to boil it down until you reach your approximate (correct) pre-boil volume (or better yet - pre-boil specific gravity), and then start your timer/hop additions.

 

[Happywanderer]

Yeah - boil it a bit longer. It'll be a bit of a crap shoot getting it right timing wise.

Likely an extra 20 mins.

 

[GHBWNY]

I did boil it down to ~ 5.5 - 6 gal and then started the 60 min hop addition, etc.. With extra hour of boiling time, I had to add water at the end, so it worked out great. Thanks, all!

 

[vance]

I second (third?) the remarks to boil it down until you reach your approximate (correct) pre-boil volume (or better yet - pre-boil specific gravity), and then start your timer/hop additions.

Is there a difference between pre boil gravity and what BS, for example, calculates as your og? Or just different terms for the same thing?

Also do you need a refractometer for that? My understanding was hydrometers are calibrated for room temp

 

[MagicMatt]

Is there a difference between pre boil gravity and what BS, for example, calculates as your og? Or just different terms for the same thing?

Also do you need a refractometer for that? My understanding was hydrometers are calibrated for room temp

Yes, "pre-boil gravity" is different than "original gravity". OG is taken after the boil but prior to fermentation. Pre-boil gravity is taken after mashing/sparging and before boiling.

Pre-boil gravity isn't really used for much other than to determine if you're in the right neighborhood for starting your boil. Beersmith (and I'm sure other programs) estimate the pre-boil gravity based on the recipe and mash efficiency variables plugged into it. It's a way to measure if you've collected enough sugars to begin your boil. If it comes in very low, then you'll know your efficiency suffered and you'll have to compensate in some way (adding DME/LME to raise the gravity, or just boiling longer but having less beer).

As for measuring, no you don't need a refractometer. It can be helpful for taking quick readings, but it isn't required. And both hydrometers and refractometers are calibrated to "room temp", but with a refractometer you're using such a small sample (just a few drops) that the sample cools relatively quickly - at least enough so to give a fairly accurate reading.

Personally, I always use a refractometer for an "on the spot" reading, but at the same time fill my hydrometer test tube with a sample and stick it in the freezer to chill to ambient temps because refractometers are not the most precise instruments (at least not the cheap plastic ones we use for homebrewing). So I use the refractometer to get a ballpark number, and if it looks right I'll start the boil. In about 10-15 minutes I'll check the hydrometer sample now that it's cooled, and take a more accurate reading. This also helps me to monitor how accurate the refractometer is reading.

Once I record the hydrometer sample's pre-boil gravity, I dump the sample back into the kettle to boil, so there's no wasted wort (the main reason people don't like taking hydrometer samples so much is how much wort is needed compared to the few drops of a refractometer).

 

[GHBWNY]

...(the main reason people don't like taking hydrometer samples so much is how much wort is needed compared to the few drops of a refractometer).

I take a 100ml sample twice with every brew, both pre- and post-ferm. Believe me, the sample never goes to waste.

 

[psujeeperman02]

On a side note, is 7 gal preboil wort a good rule of thumb to hit your 5gal bottling volume? Of course it depends upon evaporation, saturating the dry hops, etc...but I have been seeing 7gal frequently in posts and wondering how close to 5 gals everyone is getting to

 

[MagicMatt]

Personally I collect a volume of 7.25 gallons (measured at 168°F) to reach my final fermenting volume of 5.5 gallons when doing 60 minute boils. If doing a 90 minute boil, that goes up to 7.7 gallons. Both account for leaving a small amount (0.25 gallons) of kettle solids in the kettle when transferring.

But yes everyone's equipment and atmosphere is different, so YMMV.