Specific gravity in brewing is the ratio of the density of the wort to that of water.

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[WIKI] How Do You Calculate Original Gravity?

This is a community wiki post. Anybody with more than 100 reputation can edit it. You may also post your own answer. I get no reputation if you vote the question up or down, however, please vote up if ...
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Does suspended yeast contribute to high SG?

I've got a SMaSH beer (Baird Maris Otter and EKG) finishing in primary. It's been fermenting for just over a week. Starting Gravity was 1.046. I mashed at 154F for 60 minutes. Fermented with WY1335 ...
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Didn't hit gravity--how to calculate how much malt extract to add to the fermenter?

Lets say you were aiming for 1.047 but only hit 1.032. In a 5 gallon batch, how much malt extract would you need to add to the fermenter to bring it up to the desired gravity?
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Can we estimate the temperature rise in the primary due to fermentation?

OK, this is sort of cheating but I really liked this question so I thought I'd ask the question again in a slightly different way and try and answer it. I was wondering if we can actually estimate ...
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Water PH level and the effect on original gravity

What effect, if any, does the pH level of my water have on OG?
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Gravity Measurement Tools

What tools for measuring specific gravity are available to the homebrewer? EG: refractometer, hydrometer. What scale do they measure? EG: Brix, plato
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Can I measure specific gravity a day after sampling?

Often when I pour a sample to be measured, there is a good 1cm of head obscuring the SG value. It can stay around for quite some time. Can I leave it overnight in order to take the reading the next ...
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Why shouldn't we just use scales?

New on homebrew.SE, great forum here. Just a quick question - why shouldn't we just use weight scales to determine the OG and FG? My Hydrometer has broken and I can't be stuffed really buying a new ...
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Refractometer - what exactly can it measure?

I am using a refractometer to determine gravities. I am aware of course that values measured need to be corrected depending on OG of the fermenting batch. What I don't know is, what kind of sugars am ...
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Why measure gravities?

I've brewed a good dozen batches of beer from kits, extract, extract+grain, and now all-grain, and I've never measured gravities. Why measure gravity, besides to know what you're getting? Is there any ...
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Is Final Gravity a good indicator of sweetness?

This question is as simple as the title reads. In general, if I know the FG of any given beer, can that be a good indicator to me of how sweet that beer will taste? So the higher the FG, the sweeter ...
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Why is it necessary to approximate starting and finishing gravity?

In the book "Home Beermaking", by William Moore, it talks about calculating starting and finishing gravity in chapter 6. I believe that he's talking about when I get good enough at homebrewing to make ...
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what could be going on? 1065 to 1010 in 3 days and a half

This is just my first batch so I'm a complete newbie. I'm brewing a dry euro brown ale (grain + multiextract) and the temperature is between 57-67 f, but my bucket doesn't have a thermometer but I ...
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How do you calculate how much extract to add if you don't hit your target gravity pre-boil?

Planning to do my first all-grain BIAB. If miss my target gravity after mashing, how do I figure out how much extract to add before I start the boil in order to reach that OG? I would imagine ...
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How do I predict final gravity?

I've been taking the original gravity and multiplying the apparent attenuation of the yeast. For instance: 1.040 OG x 75% apparent attenuation = 1.010 expected FG But I never seem to get there. My ...
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Measuring the ABV of non beer/wine products

I sometimes make alcoholic ginger beer and alcoholic lemonade. How would one estimate the abv of something like that? Is it even possible?
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How to lower Final Gravity?

I made a Thomas Coopers Stout with 1.1kg of dark malt extract and 400g of maltodextrin and used the yeast that came with it. I got a Starting Gravity of 1.046 and Final Gravity of 1.024. Are there ...
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Why doesn't FG reach 1.000?

My second beer brew has pretty much finished its primary fermentation. It started at 1.044 and is currently at 1.014... I don't expect it will go much further. Having brewed numerous wines I ...
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Why would OG be significantly higher than predicted?

I know there are several questions on the forum about OG being lower than predicted. Please bear with me though. I'm at a loss. I just brewed a straightforward extract wheat beer recipe. The ...
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Does white honey have greater effect on gravity?

A few weeks ago I made my first mead (actually a braggot). I ordered a 12 lb bucket of raw honey. To my surprise, when I opened it the honey inside was a creamy, almost foamy opaque white. It didn't ...
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Calculating sugar in fresh fruit

Recently I made a belgian strong ale. In the secondary I added 7 pounds of fresh cherries that were pitted, frozen, thawed, and blended up. Is there a good way to at least estimate the additional ...
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Does wood affect final gravity readings?

For beer aged either in oak barrels or on oak chips/cubes, does the contact with the oak noticeably affect final gravity, and if so, what is the direct cause?
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Measuring Gravity

What is the usual procedure for measuring gravity? Is it typical to just take an original and final gravity measurement or should measurements be taken throughout? I've heard people talk about ...
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checking gravity during and after fermentation?

How could I pull out a little from my carboy to take gravity readings during fermentation? I tried to use a auto-siphon but it was a mess.
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What causes Original Gravity to be lower than it should be?

I am an extract brewer and every brew I have done the OG was lower than the intended OG, (my OG is always lower than the recipe's OG). For example I brewed the stout recipe below from beertools.com ...
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My cider stopped fermenting until I swished it around in the bucket a bunch, then continued. Is that normal?

My malted cider had been brewing after about a week in my plastic brewing bucket to the point where the little 'hat' thing in my airlock fell onto the 'neck' (no internal pressure). I opened it up ...
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Does any “probe” exist which can detect the gravity of wort?

I use a Raspberry Pi in combination with a temperature probe to measure the temperature of my wort. It would be nice if I had another probe that could measure the current gravity of my beer, so that ...
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IPA: When to Bottle

My IPA was in the primary for 10 days and gravity readings where steady before racking to the secondary. It’s been in the secondary for 13 days now and emits one bubble every 75 seconds on average. ...
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Campden Tablets to Control Final Sugar Content

I've used Campden tablets per a recipe for cider to prepare the unpasteurized cider before pitching yeast, but recently came across the following in Wikipedia: Campden tablets are also used ...
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Determining the right gravity after mash in all grain brewing

Say I am brewing a beer that is supposed to have an OG of 1.050. I'm doing all-grain brewing and at the end of my mash & sparge, if I took the gravity at that point, what should I expect? I ...
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Brewed an Oatmeal Stout and the gravity did not drop as much as predicted, should I re-pitch or add yeast nutrients/energizer?

I just brewed an oatmeal stout see recipe details here and I have a question about missing Orignal and/or Final gravities. The OG was supposed to be 1.061 and the FG 1.016. I brewed and got an OG or ...
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Hydrometer correction equation

Can you identify the constants in your hydrometer correction equation? I know that 2.6X10-6 is the coefficient of thermal expansion for the hydrometer glass; what are the others (not related to ...
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Determining the potential gravity of non-grain additions

How do you determine the potential gravity of certain ingredients? I'm sure there are charts and the like online, but, let's say you want to use a new fruit in a beer.. What are the steps to ...
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Ensuring an accurate gravity reading

So I've brewed between 6-10 batches of beer at home using partial boil methods but have never managed to get accurate gravity readings. The issue I have is that my readings somehow always seem to be ...
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Potential causes of unreliable pre-boil gravity measurement

I usually take a hydrometer reading immediately after sparge so that I can calculate total points of gravity (i.e. gravity reading * volume), and from there calculate what volume of wort I should ...
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Measuring specific gravity without sampling

Is there any way, I can measure SG with a sensor of some kind? I guess I'm not REALLY after SG, but rather a way to determine that fermantation is done, without sampling. I would very much like hook ...
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Temperature correction for specific gravity

If I want to convert my specific gravity reading from one temperature to an equivalent specific gravity at 60F how do I do it? Can you give me a correction factor for this case?
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Final Gravity on the Refractormeter vs. the Hydrometer

I've been brewing the same recipe now for several batches. It's my house beer. A Kolsch-style beer. While I have followed the same recipe for each attempt, I'm sure there has been some variances in ...
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Does a malt “late addition” affect OG?

I'm following a recipe from a book for an IPA that calls for the following (simplified) steps: Boil water (3G/11L) Add Light DME (1lb/450g) & return to boil Add hops At 45 mins, add LME ...
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Different OG than predicted

Just brewed a batch, and my OG reading is significantly different (1.051 as opposed to 1.070) than what Beercalculus.com predicted based on my recipe. Is there any possible reason for this that ...
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Why an all grain stops at 1.030 when there are an abundance of champagne yeast

I did an all-grain rye for a mash and pitched with Premier Cuvee yeast (tolerant to 18% abv), 5 grams to 4 gal wort. Repitched it again and the forced fermentation test indicates that the mash is done ...
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What gravity is suitable for not using priming sugar?

Assuming full attenuation, is there a way to figure out what gravity reading would be suitable to not use priming sugar, and just allow the excess sugar to create the carbonation? A sub-question would ...
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1answer
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Followed a recipe, made some changes, got same OG. Think it will taste similar?

I'm working on a recipe that called for some small amounts of LME (.75 lb Wheat LME, .5 lb Munich LME). I couldn't get such small amounts of LME at the homebrew store, so on some advice from the ...
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What exactly should I measure while brewing?

I want the answers to be geared towards meads/wines if possible. There seems to be so many things to measure. Which are the ones that really matter? I've started spending a lot of time taking all ...
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First brew… 1.010 gravity in 72 hours?

I'm in the middle of my first brew and I'm having some issues. Not sure if I have completely ruined this thing or what. Heres the deal... During the process, everything went pretty much as planned ...
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What can I learn from fruit beer gravity?

I just bottled a batch of a watermelon beer where the gravities going into and out of primary matched the predictions (OG 1.050, FG 1.012). I added watermelon chunks in secondary and when it finished ...
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FG dropped after wort cooled

Did a brew yesterday, hit the desired SG after the boil time - or so I thought. After cooling the wort, the SG dropped 2 points. What would cause this?
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Do I need to adjust for temperature with a refractometer?

Sorry for the simplicity of the question, but I asked Google and she didn't know. Stackexchange is my next stop. I took a brix reading of my steam beer wort at 13 brix (~1.052 SG), but it was ...
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When/How to Measure Pre-Boil Gravity to Determine Mash Efficiency

I routinely take my pre-boil gravity after sparging to determine mash efficiency so that I can throw in DME or Dextrose for a lower than expected yield or add water for a higher than expected yield, ...
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Fermentation Issues???

Fermentation Help I have need some thoughts on what I should do with this batch of beer. I am brewing a clone kit which is called Belgium Wit. The directions were a little off based on the equipment ...