Dumb Hydrometer question

[JBrady]

Im on my 9th brew and am using a hydrometer for the first time and have a question. Will preboil and post boil gravity be the same, or does the boil do something to the wort requiring me to take a OG reading after the boil only? thanks for any info.

 

[IrregularPulse]

The boil will concentrate the wort by evaporating water. This causes the post boil wort to be a high sugar /water concentration giving you a higher gravity.

 

[JBrady]

ty, I should have know that any ways, didn't even think about the pre boil volume being more.

 

[TipsyDragon]

and besides after the boil you will be topping off to your target brewing volume with water. this will also changed your gravity readings. also don't forget to adjust your hydrometer readings for the temp of the wart.

 

[The Pol]

Well, many people dont top off...

but yeah, the boil will make the SG go up.

 

[IrregularPulse]

yep, no topping off for AG brewer's or full boil Extract brewers.

 

[TipsyDragon]

yep, no topping off for AG brewer's or full boil Extract brewers.

so what you just guess how much you lost during the boil?

 

[Yooper]

so what you just guess how much you lost during the boil?

Well, no. You can calculate it, or many of us go by previous experience. In the summer, I boil off 1.25 gallons per hour, and in the winter it's .75 gallons per hour.

Volumes are more critical for AG brewing, because you want to hit a desired SG. You can take a preboil reading, and adjust your hopping, and water, add DME, etc, based on your reading. Once you know your volumes and your usual efficiency, it goes like clockwork. The first few AG batches might be very low efficiency, or conversely very high, so it's important to know your volumes. I mark the outside of my pot, but some people mark dowels or spoons to check the volume.

Also, if using a hydrometer, it's important to cool the preboil sample before using it to judge the probable OG! Even with adjustment tools, hydrometers are notoriously inaccurate at temperatures over 100 degrees.

 

[BeerCrazy]

Many brewers including pro brewers will lengthen boil to hit OG or add water. Just remeber if you use an immersion chiller that your water may not be sterile. Pro brewers often have UV chambers. If you are going to do an addition to adjust, use prechilled and adjust based on temp for based on thermal expansion. That said, it's a balancing act between exposure from water and length to cool. I just keep some extra strike water which his pasturization temp. I take a hydrometer reading before aroma hops and either lengthen time or add water if needed.

All that stated, I've got my process and equipment dialed in and have to do neither. Adjust from previous batches. It is simple science and relatively easy to control.

 

[The Pol]

I know I boil off 1.3 gallons/hour at a 70% setting on my PID. I also have my dead space calculated in all of my tuns so that I start with exactly how much water I will need. When my HLT is empty, MLT is empty... my BK has my correct pre-boil volume. I boil off my 1.3 gallons/hour and get the correct volume at the correct SG to the fermentor as my eff. never wavers from 82-83%... no guessing involved, just measurement.

It is easy to say that you will have say 80% eff. to the kettle. So you know you will have a certain SG at a certain volume going IN to the BK. Then since you KNOW how much you boil off, you also know exactly what your post boil volume and SG will be... it is linear, it is easy.

 

[Revvy]

yep, no topping off for AG brewer's or full boil Extract brewers.

That's not exactly true...I don't know where you picked that up. It's quite common to top off no matter what methodology you are employing.

There are plenty of occasions where I've had to top off. Usually no more than a half gallon. Sometimes when I'm doing a 90 minute DMS boiloff I over shoot, and need to get back to 5 gallons, depending on how strong a boil I had going.

But that's why Beersmith and other software has a "Dillution Rate" calculator in their program. You take a reading, input the amount of water you are adding, and it tells you the corrected gravity.

The funny thing is that I've ended up getting EXACTLY what the OG of my recipe should have been, after topping it off.

Lately I have been playing around, for an article, with doing 2.5-3 gallon High gravity stove top boils, over compensating for hop utilization by upping the hops in my recipe by 18%, and then topping off to five gallons, and using the dillution tool during recipe creation to help me figure out what og I am shooting for after topping off.

I've done it with a couple low IBU beers, like the AG Beligian wit I pitched on my saison kit, and they have turned out fantastically. My Belgian wit is the best beer I've done so far, and a lot of people, including a couple brewers agree.

I have a 5 gallon Marris Otter/Cascade & Centennial Ipa dry hopping now that I did the same way. So I'm excited to see how that turns out.

Even with partial mashes you top off.....It all depends on the recipe.

 

[JBrady]

Just checked my preboil after I collected 2.75 gallons which will be my post boil volume, i figured most of the sugar at that point will already be in the boil pot anyways. After a temperature adjustment with beersmith i hit a 1.070. It was supposed to be 1.072. Maybe once I added the extra gallon it will pick up a little bit more depending on whether there was a little bit more sugar left in the tun. Post boil calculations to follow..................

PS- Im scared of contaminating my brew by taking a post boil reading, thats the reason why after 9 batches of beer under my belt, this is the first one Im taking a reading on.
Any tips for a relatively new brewer???? Its a Dubbel recipe, my first time making one, and it will also be my first time drinking one when its ready.

 

[Revvy]

If there were such a risk with takiing a hydromter reading then why do you think every book, video, and forum advocates using your hydrometer?

You know, there is so much telling brewers, what not to do do you actually think folks would be saying to use your hydrometer so much? Is it a vast conspiracy to ruin millions of new brewer's batches, so that they flee the hobby and give it a bad rap?

Using basic sanitization, taking a hydrometer reading is no risk at all.

This is what I use, and it works with both buckets and carboys

And

Here's what I do....

1) With a spray bottle filled with starsan I spray the lid of my bucket, or the mouth of the carboy, including the bung. Then I spray my turkey baster inside and out with sanitize (or dunking it in a container of sanitizer).

2) Open fermenter.

3) Draw Sample

4) fill sample jar (usualy 2-3 turky baster draws

5)Spray bung or lid with sanitizer again

6) Close lid or bung

6) take reading

It is less than 30 seconds from the time the lid is removed until it is closed again.

Probably less if you have help.

And unless a bird swoops down and poops in your fermenter, you wont have any trouble.

So grow some stones little soldier and use it!!!!!!

 

[The Pol]

Man, that is a lot of wort.

 

[Revvy]

Man, that is a lot of wort.

It's just a pic off of one of the online webshots.

THough I have been using my brand new handy dandy refractometer on the last 3 brews...only trouble with that, is there is no drinking the samples.

(And I don't think licking the sampler window on it would be a very good idea.)

 

[JBrady]

ty for the good info

 

[JBrady]

10 min. left in the boil

 

[passedpawn]

I top off every batch now. After fermentation.

 

[BeerCrazy]

You could also use a refractometer and conversion tool if your worried about wasted wort. Use good sanitation and realize that CO2 is heavier than air. Beer doesn't want to become infected. It usually takes a lot of abuse to get there.

 

[jeffmeh]

It's just a pic off of one of the online webshots.

THough I have been using my brand new handy dandy refractometer on the last 3 brews...only trouble with that, is there is no drinking the samples.

(And I don't think licking the sampler window on it would be a very good idea.)

Surely one can draw the same sample that would be required for the hydrometer, take a drop for the refractometer, then drink the rest! :cross:

 

[IrregularPulse]

That's not exactly true...I don't know where you picked that up. It's quite common to top off no matter what methodology you are employing.........

Ok, let me re-phrase that, AS long as you are doing full boils and have equipment capable of handling your full boils as most AG brewers do, and you take notes to calibrate your system, you will not have to top off an AG brew. Not saying it doesn't happen, just not in the sense of a 2.5G Boil Extract batch.

I top off every batch now. After fermentation.

You add water after fermentation?

 

[passedpawn]

You add water after fermentation?

Yes. Every time. Usually with gelatin. I fill carboy up to neck.
FYI, I only do AG brews.

 

[GOOCHY]

How exactly does that work?

 

[passedpawn]

How exactly does that work?

Top off? Just dump in boiled water.

Gelatin? Do a search here, there are fine tutorials.

 

[IrregularPulse]

What is the reason for it? I understand the reason for Gelatin and have used it successfully in the past, but only enough water to dissolve the gelatin. What's your reasoning behind filling up the carboy to the neck? Just curious, not questioning methods.

 

[passedpawn]

All else being equal, more beer is better.

 

[IrregularPulse]

That's your opinion and your entitled to it. My Opinion is less non watered down beer is better. But that's the beauty of the hobby, to each their own.