If you miss OG what do you (can you) do?

I'm trying to do a better job on the details and one thing I've been bad about is knowing what my readings really mean. I have been pretty good at taking my gravity readings but after my last batch seemed too watery, I started to try and figure out what went wrong and what I could have done to fix it.

So let's assume on brew day I take readings after sparge or pre-boil and during boil or pre-chilling. Let's also assume that whatever target my recipe says that I've missed. The question then becomes, what can I do about it?

For example, my Irish Red ale had an estimated OG 1047 and I think I was at 1038. Was there something I should have or could have done about it?

Once the sparging is done, about all you can do is add some extract or boil down and accept a lower volume.

david_42 said:

Once the sparging is done, about all you can do is add some extract or boil down and accept a lower volume.

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I was thinking that the answer might be "more boiling". So what I should be doing is taking readings near the end of the boil and checking to see how close I am to the the OG? For my situation, since 1038 is below the OG target of 1047 I needed to keep going to increase the gravity.

Is there a target for post sparge but pre-boil? I normally take a reading but I don't normally see any recipe reference what this value should be.

Its simple math.

IE, if you need 5g of 1.047 post boil, you need (5*47) 235 total points.

At 7g (pre boil) , thats (235/7) 1.034 (1.03357...)

Your pre-boil reading will tell you what your post boil OG should be, assuming you get the volumes correct.

Lets say pre-boil you have 7 gallons at 1.027. Using simple ratios, that tells you if you boil down to 5 gallons, you'll have an OG of ~ 1.038. (Just use the digits after the decimal point).

So, if you wanted to bring that up to 1.047, you could boil it some more (leaving you with 4 gallons);

Or, you could have added some extract.

1 lb of Dry extract will add 44 points per gallon (potential = 1.044), or 8.8 points in 5 gallons.

47-38 = 9 points needed to get where you want to be.

9/8.8 ~ 1 lb of DME.

So, if you know your pre-boil gravity, you can just throw in a pound of DME somewhere near the end of the boil to get your numbers.

Knowing other numbers, such as the gravity of your first running, will tell you if you got conversion of the starch to sugar. Look for user Kaiser and download the spreadsheet in his sig - it will walk you through some of this. Here is a thread: https://www.homebrewtalk.com/f36/efficiency-analysis-spreadsheet-107911/

Once you have done a couple of all-grain batches, you will start to get an idea of you overall brewhouse efficiency. Aim for consistency in this number, rather than trying to simply maximize it. I run at about 75%, which works for me. This will allow you to purchase the correct amount of grain to reach the target gravities you are going for.

Get some brewing software and learn it well. Imo the 2 most important brewday tasks are nailing boil off rate and knowing your exact efficiency. Once you have these two things down, nailing your numbers is simple.

I always take a pre boil reading, and since I figure my recipes a few percentage points low, I NEVER under shoot a recipe. I may have to add a quart or two of water before boiling, but my final numbers are rarely more than a point off.

wildwest450 said:

Get some brewing software and learn it well. Imo the 2 most important brewday tasks are nailing boil off rate and knowing your exact efficiency. Once you have these two things down, nailing your numbers is simple.

I always take a pre boil reading, and since I figure my recipes a few percentage points low, I NEVER under shoot a recipe. I may have to add a quart or two of water before boiling, but my final numbers are rarely more than a point off.

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Funny you should say that because I think things started to get out of control AFTER I bought BrewSmith. Now that I have software to do some calculations I'm getting conflicts with recipes kits, books, and software.

I don't think BrewSmith has a way to use the pre boil readings. I will need to go back and look but all I can recall is places for measured OG and FG. I sure could use a calculator for the post sparge readings off the refractometer.

I would like to get a better handle on efficiency but I have a few sources on the topic and they all seem to approach it differently.

The other factor that might be an issue is so far I'm working with pre-made recipes that I order so I'm working off their calculations instead of what I am most likely going to get in my brewhouse. I assume this means that I'm unlikely to nail the listed OG.

pretzelb said:

Funny you should say that because I think things started to get out of control AFTER I bought BrewSmith. Now that I have software to do some calculations I'm getting conflicts with recipes kits, books, and software.

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Sometimes you have to take a perceived step back in order to take two steps forward. I find whenever I start working on something in my technique I used to take for granted, my first reaction is one of frustration. Then once you gradually master that part of the process, it's on to something new and you start over again. My unpredictable boil off rate used to frustrate the sh*t out of me, but now I just measure the pre-boil gravity and figure out what volume I need to have left. I don't get all worked up over having exactly 5.5 gallons post boil. If I'm a couple quarts shy, my keg is still 90% full. If I have too much, I put the excess in a two litre bottle and force carbonate with a Carbonator.

Most importantly, you can calculate your hops so that the beer is not off balance. That way, even if your gravity is off, you're not screwing up your beer.

Like others said, if you get low efficiency, you can add extract or boil down to a lower volume (again...calculate the hops accordingly.)

With high efficiency, you can top off with water and use a larger fermenter.

pretzelb said:

I don't think BrewSmith has a way to use the pre boil readings.

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It tells you your pre-boil gravity right on the brew sheet. It's up to you to make the needed adjustments. The dilution tool is handy when your numbers are to high.

If you never believe anything else you ever read again, TRUST beersmith. It may a have a few tiny quirks, but for 99% of things it is SPOT on. If you learn to use and trust it, I guarantee your beer will be better.

joety said:

My unpredictable boil off rate used to frustrate the sh*t out of me, but now I just measure the pre-boil gravity and figure out what volume I need to have left. I don't get all worked up over having exactly 5.5 gallons post boil. If I'm a couple quarts shy, my keg is still 90% full. If I have too much, I put the excess in a two litre bottle and force carbonate with a Carbonator.

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You may have hit the nail on the head here. I think my boil off rate is hard to pin down mostly because my burner is new (but so most everything). Plus I am focusing on the volume more than the gravity and I'm just learning how wrong that is.

I do like the idea of measuring the pre-boil gravity to determine the post boil volume. I need to look into that more. Part of the entire reason for this thread was me knowing I was doing something wrong and needing to learn where to improve my process.

Excess in a two litre bottle and force carbonate? Never heard of that but I can see I'm going to have to research that. Sounds interesting.

wildwest450 said:

It tells you your pre-boil gravity right on the brew sheet.

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I don't think it does, or it's an option I don't have turned on. Estimated OG is listed on the sheet along with FG but I assume OG is post boil. ProMash appears to have pre-boil from the recipes I've bought from NB.

It's up to you to make the needed adjustments. The dilution tool is handy when your numbers are to high.

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I will look into that. I haven't used it yet.

If you never believe anything else you ever read again, TRUST beersmith. It may a have a few tiny quirks, but for 99% of things it is SPOT on. If you learn to use and trust it, I guarantee your beer will be better.

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I need to start using just BeerSmith. Up to now I've ordered a kit and used both the info from the kit with BeerSmith. It's time to just enter the recipe and do what BeerSmith says. Along with what I've learned here it should help.

pretzelb said:

I don't think it does, or it's an option I don't have turned on. Estimated OG is listed on the sheet along with FG but I assume OG is post boil. ProMash appears to have pre-boil from the recipes I've bought from NB.

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You have much to learn about beersmith.

wildwest450 said:

You have much to learn about beersmith.

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I almost asked if there were two BeerSmiths.

You just made me find the option that changes the view. I had "normal" and now I've found "classic brewsheet". This should help!!

pretzelb said:

I almost asked if there were two BeerSmiths.

You just made me find the option that changes the view. I had "normal" and now I've found "classic brewsheet". This should help!!

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Yeah - use the classic one! I print that off and jot down notes on it on brew day.

I just purchased BeerSmith 2. I can't find the option that changes the view from 'normal' to 'classic brewsheet', where do you find it?

This probably isn't helpful, but I miss my gravities for just about every beer I make. I usually just shrug my shoulders and say "F it". It's still beer...