Question regarding hitting specific OG/FG readings.

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febbrewro

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Brewed three extract batches so far, and have some questions regarding OG and FG of the first two.

The first two batches were kits, but they were put together at the LHBS with ingredients off their shelf. Nothing commercial, so I'm assuming all ingredients are fresh, etc.

According to the instructions with the first kit (an IPA), it said I should hit an OG of 1.055 and an FG around 1.015. When I brewed it, I found my OG was 1.065, and fermentation topped out at 1.025. I bottled, let it sit for 3 weeks, and the final beer was good.

The 2nd batch was a porter, and according to instructions OG/FG is the same as the IPA above. However, my OG/FG ended up being 1.060/1.027. The difference this time is that I had a very vigorous fermentation for about 24 hours (enough to blow the top off my ale pale), but activity pretty much died out after that. I figured with such an active fermentation I'd get closer to the FG intended by the recipe.

My question is what can cause this, and how I can improve so that I hit the OG/FG intended by the recipes. The beer seems to come out fine, and I'm assuming this is because the OG and FG are off by the same amount (about 10 points) Thanks in advance!!

** I forgot to add that these are all 5 gallon batches. I boiled the extracts in about 2-2.5 gallons of water, and then topped off to 5 when transferring to the fermenter.
 
With extract, it is pretty hard to not hit your OG. Are you sure you have the right volumnes? Run it through some brewing software (there are some free ones online - like this) and see what it calculates the OG at - could be that the recipe is wrong.

As far as the FG - what yeasts did you use, what temp did you ferment at, and how long did you leave it? It could have just been stuck and not really finished, it could be that your temperatures were out of range and the yeast didn't fully attenuate, it could be something else. Can you give us a litte more information?
 
According to that calculator, my OG should be 54 points for both brews. My volumes may have been off slightly, but I was pretty careful with my measurements. I've read on these boards that you are supposed to mix the wort up before taking gravity readings in order to get an accurate measurement. I didn't do this, so that also might have something to do with it.

I'm not sure about the yeast used for the IPA, I have it written down at home. For the porter, I used Wyeast 1028.

The fermenters sat in my basement next to my boiler, and it stayed between 65 and 68 degrees F. The IPA was in the primary for 2 weeks, racked to secondary for 2 weeks, and sat in the bottles for 3 weeks. The porter was in primary for 3 weeks, skipped racking, and have been in the bottle for about 2 weeks now.
 
I too sometimes miss the O.G. I remember seeing a write-up not too long ago about making adjustments to your hydrometer reading based on ambient temperatures. Not too sure where the table was at, but just use "Brewgle".:D(Google). Good luck hitting those O.G.s and remember to RDWHAHB!
 
Used this calculator, just the first hit on Brewgle. http://hbd.org/cgi-bin/recipator/recipator/hydrometer.html

Ambient temp was around 65 degrees F (average temp in a Michigan basement during the winter without the heat kicked in) and it doesn't make any adjustments to the gravity since its just adjusting down to 60.

Don't worry, was very relaxed, and enjoyed a few homebrews while I was brewing batch #3 this past Saturday :drunk:

I'm rockin' the all-grain for the first time this weekend :rockin: We'll see how that goes!
 
If you are doing partial boils and topping off in the fermenter, it can be very difficult to get an accurate reading because it is tough to mix the water. The yeast will take care of that for you during fermentation.

As for your FG, it sounds like your yeast are crapping out early. Are you aerating your wort before pitching? Are you making a yeast starter?
 
I'm aerating as much as possible. I usually aerate by pouring cooled wort into the fermenter, splashing it around, topping off to 5 gallons, and then stirring vigorously with the paddle for about 5 minutes.

I've never used a yeast starter. I'm using dry yeast packets, and I was under the impression that you only really need a starter for the liquid yeast. I do give my dry yeast a good soak in warm water (about 80 degrees) before pitching. Fermentation has always kicked off pretty good within 24 hours on all batches so far.
 
That sounds like you should be adequately aerated. You also will not need a starter for dry yeast. I only asked because you had mentioned using Wyeast for the Porter. It sounds like your dry yeast should be fine.

I have to be honest and say that I have been known to use liquid yeasts without a starter (a no-no around here). I have been lucky and had the same results with and without a starter. I think the water (and bru-vigor supplied by the LHBS) here in Houston is incredible. My brews take off in 2-4 hours every time with or without a starter.
 
Well, this weekend I'm trying my hand at all grain, so hopefully I won't have any more gravity issues going that route (haha not likely!! :cross:)

I know a lot of people advocate the starter, but I've also talked to the fine people at my LHBS and they sell liquid yeast packs that are ready-to-pitch. The die hards will probably still make a starter even when using these, but I think its probably fine just to pitch. If I have a batch not turn out because of it, I'll change my tune. But until then, I'll be a rebel :D
 
I buy the out-of-date liquid yeast from my LHBS. Therefore I do starters to bring the yeast back. Yeah I'm a cheapo, but they sell that stuff for half off or more and most of the time it is only a couple weeks old and works great. I am not an advocate for using starters, but I think your on the right track with hydrating your dry yeasties and seem like you've seen success doing it your way in the past. Breward Ho I say!
 
Firstly with extract brews it's easy to get a higher than expected OG if you don't run off a bit of wort before taking your sample. Malt may not mix properly through and get stuck in the tap making you think your gravity is through the roof. Also make sure you hydrometer is reading right - should read 1000 (or very close to) in 20 degree celsius water.

Secondly I have found extract to make the least fermentable wort. Something to do with the amount of free amino nitrogen I've been told - I'll let you research further if you're interested. Since moving to AG I've found my attenuation is closer to my ealier pre-hopped kit/kilo brews than it was when I made extracts. Have a look at how much unfermentable/ partially fermentable ingredients there are in your wort (malt, lactose, maltodextrin etc). If this is a common thing (and the resulting beer is too thick or sweet) you could add in a touch of dextrose to help dry it out. If you like the taste and mouthfeel then maybe there's no need to change.

Thirdly you may simply be experiencing a stuck fermentation. Plenty of solutions for this common problem - swirling, warming, racking, adding new (started) yeast.
 
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