Alcohol content

[Cadbury]

G'day men,
When I brew a beer I generally hit the starting gravity that the recipe states on Beersmith. But my finishing gravity is always a bit lower. This means that the alcohol content comes out higher; well I think that means it does. So instead of making a 4.8% beer, I tend to get a 5.3% beer. Can someone shed some light on what is happening and how I can rectify it? I don't think my head or liver can keep going!
Thanks,
Cadbury

[drsmurto]

FG depends on a number of things.

Assuming you are an AG brewer since its unlikely extract will finish lower than beersmith predicts.....

Mash temp, water to grain ratio and length of mash including whether you are doing a step mash and/or decoctions.

Yeast strain, pitching rate and fermentation temperature.

At a guess, without knowing anything about your setup or methods, I would assume you are mashing low (65C or lower) and using a highly attenuative yeast (such as nottingham) to be going under FG.

Can you give an example of a recipe including your mash schedule? You can export beersmith recipes as a text file and then cut and paste them here.

[Cadbury]

G'day,
It would be quicker for me to drive over to your place than to put what you said onto this sight. I make 60L brews. I mash in an 85L Esky at 67 C for an hour. I use a dried American Ale yeast. I have temp control and ferment for about a week before I drop the temp to drop out the yeast. I hope this info helps. Would changing the efficiency percent on Beersmith alter the amount of grain I needed to add so I wouldn't have as much malt? Would that lower the final alcohol amount?
Cheers
Cadbury

[drsmurto]

67 for an hour shouldn't result in too low an FG.

Are you 100% sure your mash thermometer is accurate? Has it been calibrated? How long do you stir your mash after you mix the grain and water? Do you take readings in more than one place in the mash tun to ensure the whole mash is at 67C?

The dry american ale yeast isn't a monster attenuator so that shouldn't be the issue and since you are presumably using 1 packet per 20L then you aren't overpitching.

I know this question sounds too simple but are you sure your refractometer/hydrometer are accurate and that you are making adjustments for temperature?

The efficiency is based on your OG, not your FG so don't make adjustments to that. If you lower the OG and make no other changes then your FG will also drop so it wont really help with this issue.

Are you getting the correct OG that beersmith predicts? In other words, are you getting the right volume at the right OG into your fermenter that beersmith says you should have?

Lots of questions but as you have probably figured out, AG isn't that simple.

Hopefully all my questions are helping you and not annoying you.

[Cadbury]

Thanks for helping. I keep a steady temp. of 67 c for the hour and stir it for a couple of minutes every 20 minutes. I now understand about the efficiency, thanks. I take the hydro. reading prior to pitching the yeast which is approx.22 c and as far as I know my hydro. is accurate as I have two of them and they are the same. The one thing though, is I haven't had my thermometer calibrated. Could it be my temps are too high? Is this a common problem? Do people have the opposite problem of not enough alcohol?
Thanks
Cadbury