A Little Confused (maybe overwhelmed) With Gravity And When To Fix It

[Mike at Bay]

I BIAB and have posted several questions in the "General" section.....I think I need to be here.

I have done maybe a couple dozen brews that are typically kits and a recipe or two that tell me what to expect in terms of original gravity. I think I get that if I build a recipe in BF or use a kit......at some point during the mash I should take a hydro reading and see where my gravity is and see if that aligns to my expected result. Better sooner than later to know where you stand. If the reading is too low...maybe mash a little longer. If the reading is too high work to dilute (using the calculator) pre boil. Am I thinking about this right? I mostly know what happens in my kettle once I get to boil. I feel really close to grasping the basic concepts BUT I am still a bit unsure of the details to provide consistency in my process. That said, I have brew a few fine beers.

 

[Minbari]

This is how i do it, been doing it this way for 12 years. Post fermentation gravity nearly always hits this way.

1) Mash according to recipe
2) boil
3) measure SG
4) add water to correct.

The trick is to use less water vs more when you start the boil. If you want to have to 5gal at the end, figure your water amount and boil off for less than 5gal. Much easier to add water than boil more off

 

[Donoroto]

Kinda-sorta.

The mash is trying to convert all starches to sugars. You can tell if conversion is done (meaning no starches remain) by putting a drop of iodine (from the drugstore) into a few drops of wort: if it stays brownish, conversion is complete, but if it turns black, starches are still present).

So once conversion is complete, additional mash time serves no purpose*

Once fully converted, measure the gravity of the liquid. That is your pre-boil gravity. Then calculate your post-boil gravity, or “OG”, using a formula that accounts for your wort volume and boil-off rate (hold that thought).

If your calculated OG is too low, you need to boil longer. If your calculated OG is too high, you need to either boil less or add some water. Note that sometimes you need a certain boil time for hops conversion, so you can’t always ‘just boil less’.

That’s about all there is to it.

* Sometimes, you might mash longer at different temperatures to manage the conversion process. For a single temperature mash, which is most recipes, once conversion is complete more time doesn’t do anything for the beer.

Calculate dilution and boil off gravity using this calculator: https://www.brewersfriend.com/dilution-and-boiloff-gravity-calculator/

 

[Josh Hughes]

This is how i do it, been doing it this way for 12 years. Post fermentation gravity nearly always hits this way.

1) Mash according to recipe
2) boil
3) measure SG
4) add water to correct.

The trick is to use less water vs more when you start the boil. If you want to have to 5gal at the end, figure your water amount and boil off for less than 5gal. Much easier to add water than boil more off

This is what I do as well.

 

[Megary]

Once fully converted, measure the gravity of the liquid. That is your pre-boil gravity. Then calculate your post-boil gravity, or “OG”, using a formula that accounts for your wort volume and boil-off rate (hold that thought).

If your calculated OG is too low, you need to boil longer. If your calculated OG is too high, you need to either boil less or add some water. Note that sometimes you need a certain boil time for hops conversion, so you can’t always ‘just boil less’.

+1

As a BIAB brewer who always mashes in with a full volume of water, Pre-Boil gravity is the most important measurement I take. If I'm in the neighborhood of what's expected, then I boil as usual.

But if I'm off by a fair amount (define as you see fit), I have the entire boil to correct things.

If my pre-boil gravity is too high, I just boil less.
If I'm too low, I can either boil longer and accept less volume or just add a little DME or sugar.

To calculate your change in boil time, here's a handy calculation that I stole from BYO a long time ago, where gravity points are listed as just the numbers after 1.0, meaning use 50 not 1.050 etc.

Δ Boil Time =
(Pre Boil Vol (gal) * (Target Pre Boil Gravity Points - Actual Pre-Boil Gravity Points) * 60) / (Target Pre-Boil Gravity Points * Boil Off Rate (gal/hr))

 

[J A]

You should use the same mash/sparge routine pretty much every time, whatever the recipe is, sometimes with some variation in the infusion temp. Figure out how to hit your strike temp accurately and keep the temp range constant for the duration (1 hour is common). Projected OG is going to be based on full conversion of the grain being used. Your conversion efficiency is going to be the variable that gives you higher or lower OG on any particular brew.
Once you've mashed and sparged and you have an accurate pre-boil volume, that's a good time to take a gravity reading - be sure that your wort is well mixed and your sample is proper temp. You can make some adjustment then if it's needed by boiling off extra volume, adding extract or, (unlikely) topping up to dilute. Unless it's enough to alter hop and IBU interaction, don't bother.
Once you've boiled -your boil off is predictable - you should be at the proper OG if you started with the right pre-boil gravity and you have your boil-off rate figured out.

 

[Dave Y]

I BIAB and have posted several questions in the "General" section.....I think I need to be here.

I have done maybe a couple dozen brews that are typically kits and a recipe or two that tell me what to expect in terms of original gravity. I think I get that if I build a recipe in BF or use a kit......at some point during the mash I should take a hydro reading and see where my gravity is and see if that aligns to my expected result. Better sooner than later to know where you stand. If the reading is too low...maybe mash a little longer. If the reading is too high work to dilute (using the calculator) pre boil. Am I thinking about this right? I mostly know what happens in my kettle once I get to boil. I feel really close to grasping the basic concepts BUT I am still a bit unsure of the details to provide consistency in my process. That said, I have brew a few fine beers.

You've gotten some great feedback by some really seasoned brewers already. I'll throw in a few pieces of eight.
I prefer to correct gravity pre-boil.

First, All in one systems are a little different and -generally- not as efficient due to size constraints. See also: https://www.brewersfriend.com/forum/threads/all-in-one-brewhouse-help-thread.17832/

You are thinking about this right. Most recipes cater to the "least common denominator" brewer and instructions. For all grain, those instructions come with an "assumed level of knowledge" that even seasoned extract & partial mash brewers may not have. The analogy "your mileage may vary" applies.
Get and use a refractometer during the mash. It's not as precise as a hydrometer, but, you don't have to cool the wort or do math to get a basic gravity reading. Just make sure you know the offset to your hydrometer. KNOW your boil off rate.

On my Anvil systems I've never reached full volume mash target gravity or reduced volume + sparge in 60 minutes flat. I haven't done a full volume/no sparge brew in a couple years now, but the best I've gotten is about 75 minutes. So that's part of my process now; I count on about 75-90 minutes mash time. Typically, I mash, mash out, sparge to pre-boil volume. I start taking readings with a refractometer about 45 minutes in. Sometimes earlier if I'm feeling impatient. Once I've got my volume I raise the temp on the kettle from ~170 to ~200, move the malt pipe, stir the wort and get a reading on the refractometer. Another part of my process is instead of brewing for 5 gallons on the nose, I target 6.5 gallons post boil. The transfer to the fermenter will leave about .25 gallons-ish in the kettle. If I harvest yeast when the fermentation is done, I'll get about another quart of 'beer' in the process and I'll leave about another quart in the fermenter below the pickup tube. If I'm spot on I've got between 5.5 and 5.75 gallons of beer. Now I have options.

If I need to lower the gravity, I will either sparge a bit more or just add some sparge water directly to the wort, stir and reassess.

Typically I make numbers pretty consistently because I do not rush to leave the mash but if it's close, I can fix with a longer boil -adding a few minutes PRE-HOP-SCHEDULE if I'm a bit low. If I'm high and it's significant - I'll either adjust the recipe if needed for the hops or sparge a little more and add a partial 2.5 gallon keg. When I did my Roggenbier, I counted on lower efficiency but got better efficiency than expected in the mash. I ended up with ~ 7 gallons of beer. Other times I've had poor mash efficiency ( underestimating just how many rice hulls were needed ) and boiled away my 'overhead' volume to get the numbers.

Unless you're way off, the number for SG & OG are like the pirate code - more like guidelines than actual rules.

 

[Mike at Bay]

Thanks all. Let me start with a couple of successes!!! My all grain BIAB Blonde ale and Peanut Butter Cup Porter both turned out well. An expert may have things to say about the flavor but hell....they both taste like (or nearly like) the beers I expected. The porter could have stronger peanut butter flavor but I am not complaining. Numbers were close on both.

I have two extract brews in fermentors. A Sierra Nevada Clone (replaces my dumped all grain version) and another porter...

I do have a question for you all about the porter.....this recipe calls for an English yeast that I don't have on hand. I have ordered and it will be here tomorrow. The question......use my Safale 05 today....just went into the fermentor at 4:30 ET 2/3. Or wait for the English yeast to come tomorrow?

 

[Josh Hughes]

English yeast will have more fruitiness to it than US05.

 

[Minbari]

Thanks all. Let me start with a couple of successes!!! My all grain BIAB Blonde ale and Peanut Butter Cup Porter both turned out well. An expert may have things to say about the flavor but hell....they both taste like (or nearly like) the beers I expected. The porter could have stronger peanut butter flavor but I am not complaining. Numbers were close on both.

I have two extract brews in fermentors. A Sierra Nevada Clone (replaces my dumped all grain version) and another porter...

I do have a question for you all about the porter.....this recipe calls for an English yeast that I don't have on hand. I have ordered and it will be here tomorrow. The question......use my Safale 05 today....just went into the fermentor at 4:30 ET 2/3. Or wait for the English yeast to come tomorrow?

I use 1098 for porters all the time. Pairs nicely

 

[Mike at Bay]

I use 1098 for porters all the time. Pairs nicely

Thanks. British yeast arrives tomorrow and beer is still cooling so I will wait for the English.

 

[Craigerrr]

Not sure which English yeast you are referring to, I use Fermentis S-04 in my Coffee Porter, and used it in @Minbari 's Stout, great yeast for either style in my opinion.

 

[Dave Y]

The porter could have stronger peanut butter flavor but I am not complaining. Numbers were close on both.

Look up how to brew a schwarzbier - the German dark lager. The one word that I kept running across when I was reviewing the style was 'restraint'. IMO, the best use of adjuncts in a beer is when the consumer:
1) likes the beer (enough to pay for it)
2) wonders 'hey, what's that flavor I'm tasting?' or 'what's that aroma?'
3) bonus points if the consumer from #2 above is a BJCP judge or active on Untapped, which I've heard is one of @Bigbre04's favorites... ;-)

You don't want the components of the beer out of balance and doubly so when you're working with adjuncts, sugars, honey, agave, molasses, corn, etc. Even when you have your elements out of balance, the beer may taste good to you, but you may be the only one who likes it.

Water, malt, hops & yeast are the elements here, with malt, hops & yeast being the 'air, earth & fire'. You may have some skew - examples being malt forward lagers, hop forward IPAs, yeast influenced Belgian or Weiss beer but it isn't dominated by that characteristic. Yes, you can shoot for 90 IBUs in a session IPA, but it's not going to appeal to many, maybe not even you after a while.

In years past, I would brew recipes I ran across either by LHBS suggestion, magazine etc. My wife found a recipe card in a magazine I'd read; raspberry jalapeño ... Basically, a Pilsner base, with some raspberry & a bunch of jalapeños added post fermentation. I was a bit skeptical at first but decided to have a go. It worked. Served at Brit ale temps, it was pretty good, but the peppers made gave the beer a very distinctive bite that not all beer drinkers want. Really fun fact, the colder the beer was served, the hotter the pepper character. I had several bottles down in the brew area, but not cold. Was visiting a neighbor and threw a few bottles in the freezer for an hour before going over. H*ly cow was that HOT. and very cold at the same time. Pretty interesting, but I've never done it again because that 5 gallons of beer went very, very, very slowly. Neighbors weren't a fan after a few sips and by the end I was glad to be done with the last bottle.

Congrats on making some decent beer !

 

[J A]

Pretty interesting, but I've never done it again because that 5 gallons of beer went very, very, very slowly. Neighbors weren't a fan after a few sips and by the end I was glad to be done with the last bottle.

Novelty beers are problematic, especially when it comes to distinctly "non-beer" ingredients and flavors. I still see dill pickle beers around occasionally. I've never tasted one and I'm pretty sure I'm not missing anything.
Even lime-flavored beers are off-putting IMO. Lime and salt on the rim of the glass is one of the best things ever during the summer heat in Texas, even with the lime sqeezed and thrown in to float in the beer, but somehow the flavor built into the beer doesn't hit the same way and always tastes off to me.

 

[Bigbre04]

@Dave Y Triggered.

I have a black lager that i brew for about 3/4 of the year that is a super popular beer for me. love it.

On day 2 of 3 back to back brew days... packaged 3 of my tanks from last week so far and will have refilled 2 of them this week!

 

[Minbari]

Novelty beers are problematic, especially when it comes to distinctly "non-beer" ingredients and flavors. I still see dill pickle beers around occasionally. I've never tasted one and I'm pretty sure I'm not missing anything.
Even lime-flavored beers are off-putting IMO. Lime and salt on the rim of the glass is one of the best things ever during the summer heat in Texas, even with the lime sqeezed and thrown in to float in the beer, but somehow the flavor built into the beer doesn't hit the same way and always tastes off to me.

Dill pickle beer is as bad as you think it is, lol

 

[Bigbre04]

Dill pickle beer is as bad as you think it is, lol

2 breweries in my area do pickle beers...one of them has it year around. Not for me honestly, but some people like them alot.

 

[Minbari]

2 breweries in my area do pickle beers...one of them has it year around. Not for me honestly, but some people like them alot.

I didn't even finish it. Maybe someone makes a good one, this tasted like Budweiser with pickle brine in it. . Gross

 

[Bigbre04]

I didn't even finish it. Maybe someone makes a good one, this tasted like Budweiser with pickle brine in it. . Gross

i split a 4 oz pour with the gf. which means that i had 3.5oz and she had a sniff and a sip. it is very heavy on the garlic and pickle brine flavors... too strong for a full pour.

BUT they do have it on draft all the time, so some sadists must enjoy it.

 

[Dave Y]

I have a black lager that i brew for about 3/4 of the year

Black Lagers Matter

Dill pickle beer is as bad as you think it is, lol

Yeah, the local brewery has one of these, and a salted pilsner - people do buy them in the summer. I tried the salted pils, and it wasn't horrible. I couldn't get past the aroma on the pickle beer. Nothing wrong with pickles, they belong on hamburgers though, not as an ingredient in beer.
Be right back, gotta go tell some homeys to get off my lawn ;-)