All Grain F.G.

What went wrong? Was this supposed to happen? Should I throw it out? What do I do now?

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All Grain F.G.

Postby stouts » Sun Nov 03, 2002 6:31 pm

hey all,
I did my first all grain the other day and I racked it after 4 days and left it in the secondary for 12 days.
It's supposed to be a Sierra Nevada Porter clone,
but the F.G. was only down to 10.20, is it possible that i didn't efficiently get all the fermantable sugars out of the grain?, or could i have done something else wrog?
btw= it still tastes ok but the ABV is just gonna be a little low, any suggestions?
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yeastie beasties

Postby Gravity Thrills » Sun Nov 03, 2002 7:29 pm

My best guest is not anough aeration at pitching to get yeast to fully attenuate, or not a large enough volume of active, vigorous yeast at pitching. This topic has come up a couple of times in the last month here. Check out the archives for possible remedies, or don't sweat it if it tastes good.

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Things to record during the brew.

Postby Brewer2001 » Sun Nov 03, 2002 10:08 pm


You need to check several things.

Determine your L/G ratio. 2/1 is 1 qrt H2O to 1lb. of malt. (2/1 is a good mid range)
Calculate the correct strike temperature to get the required mash temperature. (I mash in at 170-180F to get a mash temperature between 148-154F).
Maintain the correct temperature throughout the mash. Take temperature readings at mash (adjust if required) and at mash out and record all your readings.
Do the iodine test to check for complete conversion. (for lighter beers) In a white cup draw off a small sample of wort and add a drop of iodine. If it becomes clear conversion is complete, if black starch is present. DUMP THIS SAMPLE!
Calculate the amount of sparge water required at the correct pH. If you under sparge you won't get all the wort, over sparge and you draw out tanins. Try to keep the sparge water between 160-168F at 5.2 - 5.8 pH.
Take as many hydrometer readings as possable.
First runnings...log it. (at run off)
Last runnings....log it. (during sparge to determine when to stop. Stop at 1.010)
Kettle (pre boil)...log it.
Kettle (pre boil,post adjunct additions)...log it.
Primary (at transfer) Original gravity...log it!
Secondary (at transfer) Final gravity...log it!

This will not help this batch but will arm you with all the information about the batch. After you brew all mash these things will become instinctive but for now you need notes to review.

I agree with Jim that you may have underpitched. Note the quantity of yeast pitched and its age. Aerate the wort well before pitching (I use O2, it really helps). I don't know what your O.G. was but I would try to get the F.G. down below 1.012.

Keep brewing....Have fun.

Tom F.
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my experiences with ALL grain

Postby Fraoch » Mon Nov 04, 2002 2:18 am

Many english breweries will add a certain amount of sugars to thier brews,simply because it is hard to ferment an all grain batch down to say 1012 or so,theoretically, the sugars ferment out leaving little or no gravity and the malt flavour is derived from the grain. When i make beers that contain no sugars which is all of them, if it is a darker beer ie containing black malt, chocolate etc i find that they dont necessarily brew out to where you would like them to due to the large amount of dextrins contained within.The problem was not due to yeast performance( the beauty of open fermentation for the primary is that the performance of the yeast is obvious, if it is not "brain of morbius" at least 2" thick then you may have under aerated.The yeast cake should be extreme!!!Great swathes of the stuff!)After much experimentation i found that lowering the mash temp to 65c for a pale ale to 62c for a porter containing around 10% of black malt gave me an SG of 1048 and FG of 1014. Still 1002 off my required mark, but it is very malty and !@#$ good, not dry at all. This may be your problem, an Fg of 1020 is fine but you expected more alcohol. Check your malts, they may only contain 65% fermentability,in an ideal world everything will brew out to 1/4 Og for primary, but it doesnt always work like that.Check your malts, your mash temp, grain to liquor ratio ( thinner mash = more fermentable) yeast performance and your recipe.
hope i may have been of some help,
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