So I’m a new brewer (obviously) and one thing I’m not understanding is this…
All of NBs kits specify OG (which I understand), but they never specify a target FG. So how do I know when I’ve reached my target FG for a particular recipe or if my fermentation has stalled and I need to maybe add more yeast?
Is it a matter of personal taste for a given recipe?
Fg is largely dependent on the strain, quantity, and freshness of the yeast that is pitched. That is too many variables to give a FG with any accuracy.
J
You have reached your FG when three successive SG readings over three to four days are the same. There are some fermentation problems which may not let you achieve a typical FG for the recipe. That would be another post question with the details of your brewing process if that happens.
If you bulk age in a secondary a raise to room temperature is usually warranted. Keep your secondary covered, same as primary.
That statement right there is what I’m referring to. How the hell do I know what a “typical” FG for the recipe is?
That statement right there is what I’m referring to. How the hell do I know what a “typical” FG for the recipe is?[/quote]
Check what the typical FG is for the style you’re making…http://www.bjcp.org/2008styles/catdex.php
It’s been posted before, but always needs to be emphasized:
You really can’t tell if you’ve reached a FG without taking hydrometer readings.
If you get the same SG on 3 successive days, then you’ve reached FG.And that’s no matter what your recipe says FG should be! Yeasties do want they want, and don’t read the recipe. 
That statement right there is what I’m referring to. How the hell do I know what a “typical” FG for the recipe is?[/quote]
Check what the typical FG is for the style you’re making…http://www.bjcp.org/2008styles/catdex.php[/quote]
This is a good resource, but I feel like it’s so general. For example, there’s no mention of a double IPA or imperial IPA which tend to have higher OGs. There must be a more scientific way to approach this.
[quote=“James Rausch”]It’s been posted before, but always needs to be emphasized:
You really can’t tell if you’ve reached a FG without taking hydrometer readings.
If you get the same SG on 3 successive days, then you’ve reached FG.And that’s no matter what your recipe says FG should be! Yeasties do want they want, and don’t read the recipe. [/quote]
Yes, I understand how to use a hydrometer. The point is, the recipes don’t tell you what your FG should be. There’s a good chance, especially on higher gravity beers, that your fermentation could stall. So if you dont know what FG you are aiming for, you don’t know if you have a stalled fermentation or you have completed fermentation of an appropriate amount of fermentable sugars for the particular style.
Beersmith has helped me really watch and target SG/FG. Not to mention its a backup of your info incase your note book comes up missing. They offer a 20 day free trial. Give it a try for your next brew day I think you will be happy. I only did several batches of extract before going all grain so I think there will be a slight swing in fermentability from manufacture to manufacture for similar LME/DME products.
You can get a rough idea by knowing the attenuation of the yeast and the OG. For example, Wyeast’s 1056 attenuation is ~75% meaning it should consume 75% of the fermentables, if your OG was 1.060 the yeast should consume 45 points of that so your estimated FG would be 1.015.
Thanks Glug, this is what I was looking for.
[quote=“Chris-P”]
This is a good resource, but I feel like it’s so general. For example, there’s no mention of a double IPA or imperial IPA which tend to have higher OGs. There must be a more scientific way to approach this.[/quote]
Look closer…http://www.bjcp.org/2008styles/style14.php#1c
Thanks Glug, this is what I was looking for.[/quote]
But the fermentability of the wort is what makes the difference. The attenuation rating of the yeast is for comparing one yeast to another using a standardized wort. It has little bearing ion the attenuation you can actually expect. Using the same yeast, I can get anywhere from 65-85% attenuation depending on the wort I pitch it into.
Thanks Glug, this is what I was looking for.[/quote]
But the fermentability of the wort is what makes the difference. The attenuation rating of the yeast is for comparing one yeast to another using a standardized wort. It has little bearing ion the attenuation you can actually expect. Using the same yeast, I can get anywhere from 65-85% attenuation depending on the wort I pitch it into.[/quote]
Fair enough. Makes sense. Thanks Denny.
A calibrated hydrometer is needed also.
My local club held a calibration night. Distilled water was maintained at a constant temp (lab thermometer) with a water bath. I needed to add a lot of nail polish to get my reading to be correct.
FG is one of those things that you’ll have to get used to. it takes a while to dial down, but you will start seeing trends in your system that affect FG. mash temp, grain bill, attenuation will all do this. I’ve found the best way to accurately estimate my FG is via experience brewing on my system. I wish there was a better way to figure it out, but there are just too many variables.
Denny’s advice is the best starting point
The thing is if he’s brewing with extract he has little control over the fermentability of his wort so using the yeast’s attenuation number will get him in the ballpark for a starting point. That said, when I brewed with extract kits my attenuation was usually 5-10% below the manufacturer’s.
+1
i assumed he was doing AG. when i was doing extract my attenuation wasn’t very good either. I regularly got FG around 1.015-1.020
The best way to lower your FG with extract is to replace part of the extrat with sugar. When I was developing the kits of my recipes for NB, I found doing that got the FG right where it should be.
