[scarecrow]

I recently did the British Ipa from Dave Millers book on brewing. all grains recipe. Mashing was done at 154 degrees with 3 gallons of water. My HLT was at 170 with another 5 gallons. After mashing my gravity was at 1.054.  I now had close 7 gallons of wort. I started boiling and pitched my first set of hops. 55 minutes into the boil I added the last of the hops.. Using a wort chiller I cooled the wort down to 100 degree before transferring it to a carboy. My gravity now is 1.032. I am completely lost as the recipe says it should be at or above 1.050 and its lower. What did I do wrong on this brew being as this is my 2nd time doing all grain I'm not sure if I missed something or not.

[yso191]

Preboil gravity is nearly impossible to correctly measure until the boil has begun.  Even when it is stirred it seems to stratify or something.  Did you have a way of predicting your mash pH?  That can throw your efficiency way off.  But the usual culprit is not milling fine enough.

[scarecrow]

milling was done at the store when I bought the grains. I took the pre-boil G directly from the mash tun right before I started sparging. So is a pre-boil really needed for anything? Oh and should I toss the entire thing and try again or is there anything I can add it has only been 24 hours so far.

[GS]

As much as I hate to say it, I think your record keeping is off. All things being equal, it is not possible for a post-boil gravity to be lower than a pre-boil gravity. The numbers you give seem to be reversed. 1.032 would be about the right pre-boil gravity for a post-boil of 1.054.

But what have you got to lose? I certainly wouldn't toss the batch. Finish it, and let us know how it turned out!

[Slowbrew]

milling was done at the store when I bought the grains. I took the pre-boil G directly from the mash tun right before I started sparging. So is a pre-boil really needed for anything? Oh and should I toss the entire thing and try again or is there anything I can add it has only been 24 hours so far.

Taking your reading at that point would give a number more akin to first runnings.  The sparging process would dilute things from that point. 

I always take my pre-boil reading immediate after the hot break in the kettle.  Not technically pre-boil but is worked me.

Paul

[pete b]

Yes, you measured your first runnings, not your pre boil, which is the entire volume after sparge.
The only important number is the post boil gravity. Did you cool your gravity sample to the temp that your hydrometer is calibrated t?. This is on the piece of paper that comes with your hydrometer. I use Denny's trick of putting some wort in a cocktail shaker and putting that in an ice bath.
The next time you get malt ask them to double crush it, this may improve your efficiency. In the last few minutes of the boil cool a sample and take a reading. If your gravity is say 3-6 points low you can simply boil off more water for 20 minutes. If it's more than that make sure you have some light malt extract around and you can add that to make it up. Online calculaters can help figure out how much. If you are within a couple points no worries. If you are still way off look into pH.
Once you have a good crush and you know pH isn't out of whack and you still consistently run on the low side with your gravity just assume a lower efficiency with your system and use more malt. Within reason all that matters is that it can consistently be predicted.
I

[HoosierBrew]

So is a pre-boil really needed for anything?

Yeah, it gives you an idea of what your OG will be after the boil. If it's lower than expected you can either add some DME to the boil to compensate, boil longer,  or just go as is if it's fairly close. If it's higher than expected you could shorten the boil a bit or go as is. Either way, it helps to know whether or not you got in the ballpark with your mash.

[kramerog]

So what can you do with the mash gravity reading you took?  Compare it to the 1st table at http://www.braukaiser.com/wiki/index.php?title=Understanding_Efficiency.

[reverseapachemaster]

You could add extract to the beer to increase the fermentables that you ended up not receiving from the mash.

[pete b]

So is a pre-boil really needed for anything?

Yeah, it gives you an idea of what your OG will be after the boil. If it's lower than expected you can either add some DME to the boil to compensate, boil longer,  or just go as is if it's fairly close. If it's higher than expected you could shorten the boil a bit or go as is. Either way, it helps to know whether or not you got in the ballpark with your mash.

I mistakenly gave the impression that the pre boil gravity is not useful. Its definitely useful especially when dialing in your system, but at that point you really don't know your boil off so a check at the end of the boil is often the most useful for adjusting by boiling longer or adding extract.

[beersk]

milling was done at the store when I bought the grains. I took the pre-boil G directly from the mash tun right before I started sparging. So is a pre-boil really needed for anything? Oh and should I toss the entire thing and try again or is there anything I can add it has only been 24 hours so far.

I always take my pre-boil reading immediate after the hot break in the kettle.  Not technically pre-boil but is worked me.

Paul

Same here. I always get very conflicting readings if I take them before the boil starts. Like Steve said, there's some odd mixing up that happens that screws the readings before it boils.

[scarecrow]

Yes, you measured your first runnings, not your pre boil, which is the entire volume after sparge.
The only important number is the post boil gravity. Did you cool your gravity sample to the temp that your hydrometer is calibrated t?. This is on the piece of paper that comes with your hydrometer. I use Denny's trick of putting some wort in a cocktail shaker and putting that in an ice bath.
The next time you get malt ask them to double crush it, this may improve your efficiency. In the last few minutes of the boil cool a sample and take a reading. If your gravity is say 3-6 points low you can simply boil off more water for 20 minutes. If it's more than that make sure you have some light malt extract around and you can add that to make it up. Online calculaters can help figure out how much. If you are within a couple points no worries. If you are still way off look into pH.
Once you have a good crush and you know pH isn't out of whack and you still consistently run on the low side with your gravity just assume a lower efficiency with your system and use more malt. Within reason all that matters is that it can consistently be predicted.
I

Pete
I did not cool the post boil to the ambient air temp. The temp was 100 degrees, could this be where I'm getting this at.

[crakers540]

As has been stated, you MUST take your gravity readings at the temperature that the hydrometer is calibrated for.  If nothing else, for trending, at least make sure you always take gravity readings at the same temp.  Temperature of a liquid will vary the gravity drastically.  Take the gravity of maple syrup at room temp, then at refrigerator temp.  The hydrometer will move down in the room temp syrup and give you a reading (perhaps), but will most likely fail to penetrate a half inch in the refrigerated syrup.

[RPIScotty]

As has been stated, you MUST take your gravity readings at the temperature that the hydrometer is calibrated for.  If nothing else, for trending, at least make sure you always take gravity readings at the same temp.  Temperature of a liquid will vary the gravity drastically.  Take the gravity of maple syrup at room temp, then at refrigerator temp.  The hydrometer will move down in the room temp syrup and give you a reading (perhaps), but will most likely fail to penetrate a half inch in the refrigerated syrup.

You can always use correction as well. I don't wait to cool samples to 60F.

[BrewHalla]

Your numbers just don't make sense to me or is there something i am totally missing. I don't know exactly what setup and method you're using to brew but you say you mashed with 3 gallons of water.. how many pounds of grain were in the bill as this seems too low to me off hand. If you have 10 pounds of grain my math would put me in the 5 gallon range... then you say you ended up having a total of 8 gallons all together in the mash tun but was able to extract 7 gallons.. grain tends to hold 0.2 gallons of water per pound... and you only lost 1 gallon of water..(that gives only a 5lb grain bill). But like I said maybe I am missing something

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