Original Gravity Low

[Plastic Brewkettle]

Is it realistic to hit original gravities as a garage brewer? I have never hit an expected OG. I hit my mash temperatures. The literature is unclear about wash process (since I don't know the proper term). After mash, we're supposed to pull off the water from the bottom of the mash tun and pour it back over the grain, correct? I have been collecting and pouring the amount of strike I put in, eg, 6 gallons in, 6 gallons recirculated. I drain off my wort super slow, like 1 gallon per 20 minutes. I go with a 7.5 gallon boil because that seems to be a good amount to drain off without getting any sludge.

 

[day_trippr]

I expect "wash process" = "sparging". That is, using water to rinse out mash sugars beyond the initial runnings.

As for the question: yes, it is totally realistic to "hit the numbers" - which start with pre-boil gravity and pre-boil volume.
If you can nail just those two metrics reliably, everything else follows automagically.

To get there one needs to have characterized their brewing equipment and process, understanding where losses occur, etc.
But it can be done. I'm more a "basement brewer" but I rarely miss a "number" on a repeat recipe, and similar recipes reliably produce similar outcomes...

Cheers!

 

[Sam_92]

Are you getting exactly 5 gallons in your fermenter? Usually we assume 1 gallon of water boiled off per hour of boiling, if that's the case you're ending the boil with 6.5 gallons of beer and your gravity will be lower than the recipe for 5 gallons predicted. You said "without getting any sludge" makes me think you're leaving wort in the kettle with the proteins that coagulated but you'll also be leaving sugar behind.

In my system I aim to get every drop from the kettle into the fermenter because I have a problem with seeing sugars go down the drain. No matter how murky the wort is in the kettle, it all drops out in the fermenter and you get crystal clear beer as long as you give it enough time.

 

[Plastic Brewkettle]

@day_trippr I have been only taking readings post boil. Are the OG numbers supposed to be pre-boil numbers?
@Sam_92 I guess I have been leaving a lot in the kettle. Should I be straining the last of it and using a 6.5 gallon boil? I did that with a recent batch but the numbers were still low.

 

[day_trippr]

[...]
After mash, we're supposed to pull off the water from the bottom of the mash tun and pour it back over the grain, correct? I have been collecting and pouring the amount of strike I put in, eg, 6 gallons in, 6 gallons recirculated.

I believe you have over-indulged in the procedure known as "vorlaufing" - the process of drawing some wort from the mash tun and then pouring it back on top of the mash. This is intended to clear out any debris that might have made it through a false bottom or other lautering mechanism before running the wort to the boil kettle. Typically, one only "vorlaufs" - or returns - a few quarts of wort drained from the mash tun to the top of the mash, not for the entire mash volume.

I drain off my wort super slow, like 1 gallon per 20 minutes. I go with a 7.5 gallon boil because that seems to be a good amount to drain off without getting any sludge.

Do you perform any type of "sparge" process, or are you putting the entirety of your brewing water budget in the mash tun from the start?
Depending on the process you use, you could probably do your run-off a lot faster...like at one quart per minute, or better, with no loss of yield...

Cheers!

 

[Plastic Brewkettle]

@day_trippr After I vorlauf (I don't speak German so I am just using the English equivalent) I do add sparge water to the mash tun as I drain off the wort. As a gallon drains off, I add a gallon from the hot liquor tank.

 

[day_trippr]

@day_trippr I have been only taking readings post boil. Are the OG numbers supposed to be pre-boil numbers?
[...]

Most recipes only specify the gravity of the wort into the fermentor(s) - so all volume losses have been effected, including boil-off, cooling shrinkage, and equipment losses.

But, one can use brewing software (eg: Beersmith) that can back-calculate things like post-mash/pre-boil gravity and volume, so one can actually be aware of a divergence from the recipe's predictions in time to do something about it, if desired...

Cheers!

 

[day_trippr]

@day_trippr After I vorlauf (I don't speak German so I am just using the English equivalent) I do add sparge water to the mash tun as I drain off the wort. As a gallon drains off, I add a gallon from the hot liquor tank.

lol! Any German I "know" is incidental. Like "vorlauf"

Ok, so that's a good piece of information: if you are adding sparge liquor atop the mash then you are doing some variation of "fly sparging".
I do this as well, but I draw the wort off at 1 quart per minute while adding hot water to the mash tun at the same rate, until I have the prescribed "pre-boil" volume of wort in the boil kettle. That's a fairly typical rate for the process...

Cheers!

 

[bracconiere]

Is it realistic to hit original gravities as a garage brewer? I have never hit an expected OG. I hit my mash temperatures. The literature is unclear about wash process (since I don't know the proper term). After mash, we're supposed to pull off the water from the bottom of the mash tun and pour it back over the grain, correct? I have been collecting and pouring the amount of strike I put in, eg, 6 gallons in, 6 gallons recirculated. I drain off my wort super slow, like 1 gallon per 20 minutes. I go with a 7.5 gallon boil because that seems to be a good amount to drain off without getting any sludge.

as below, a vorlauf is just to clear the first runnings.basicly compacting the grains as a tighter filter, kinda like 5 micro, instead of 100 micron, then once that's accomplished, you use kinda warm water to (i still say push the sugars down) and out of the grain bed with fresh water....into a BK...but the goal is to, for my fly spargeing, continously dilute the grains with fresh water as you go, that way none of the sticky sugar is lost hanging out with their mom like a 30 years old still living at home....

I believe you have over-indulged in the procedure known as "vorlaufing"

beat me to it....

 

[bracconiere]

@day_trippr After I vorlauf (I don't speak German so I am just using the English equivalent) I do add sparge water to the mash tun as I drain off the wort. As a gallon drains off, I add a gallon from the hot liquor tank.

is there a chance of pitting? how do you spread it out over the grain bed, and how much do you keep above the surface?

 

[day_trippr]

"pitting"?
Is that like "channeling" - sparge liquor taking a path that avoids the best of the grain bed?

Cheers!

 

[Sam_92]

And if it's a fairly consistent thing you can always just add an extra pound of grain, it'll cost about 2 bucks max.

I know that I consistently get 75% efficiency so I build my recipes based on that. I could target more but all the methods of eking out efficiency take more time and I have more money than time (just barely but it does win out).

To give an example of what I'm thinking here let's say you're brewing a recipe that should start at 1.060. You can calculate total sugars in the beer by multiplying volume by gravity (5*60) and you get 300 gravity points in the kettle. If you leave a gallon and a half in the kettle because it's full of trub then the volume of the beer is 6.5 gallons and the gravity in your fermenter is 1.046. That's a huge difference!

 

[bracconiere]

Is that like "channeling"

YES!

 

[Plastic Brewkettle]

@bracconiere I use a large strainer with sparge arms. That's all I have.
@day_trippr I may be draining too slowly? That's a comfort. I have a problem with patience.

 

[bracconiere]

I use a large strainer with sparge arms. That's all I have.

do you do the recomended of keeping 2"s of sparge water above the surface? other wise i've heard day_trip might be right and channeling......


WAIT!!! is your effec too HIGH, or low?


most recipies assume 75% i usually get 85% or so, i just say whoppidty....

 

[Plastic Brewkettle]

@bracconiere If I keep 2"s of water above the grain, I'll leave a lot of water/wort in the mash tun, right?
" WAIT!!! is your effec too HIGH, or low?" I didn't get it. Please explain.

 

[jrgtr42]

So the big question is, how far off are you from the expected OG?
And where are you getting those numbers?
I usually input my recipes into brew software - I use BRewers Friend. over time, I've tweaked my profile for my system, though TBH I didn't really need a lot of tweaking - my numbers were pretty durn close using the stock ones.
I personally don't need to hit EXACTLY where the predictions are - I don't take malt batches and such into account, like some here do. If I hit within .005 of the expectation, I'm happy and move on with no worries.
Using the software is more to give me a rough idea what I should expect on a new recipe; some of the ones I brew repeatedly |I don't even bother with opening it up, I know what to expect so I just keep notes on the numbers I hit.

 

[bracconiere]

If I keep 2"s of water above the grain, I'll leave a lot of water/wort in the mash tun, right?

no it will keep the sparge water even through the grain bed, and prevent "chanelling"....and sugar doesn't dissolve instantly in water, which is why i consider sparging pushing the sugar down...

and honestly i wasn't sure if you were trolling, your OP just said you wern't hitting the recipie OG, and everyone 'just' assume it was low...

but yeah you want to keep the sparge water at least 2" above the grain bed....i usuall fill my Mash tun up above the grain bed about 6", then being i don't have a fancy tunned fly sparging setup, just take a break then when it gets down to about an 1" fill it back up, running slow the whole time....

edit: now i see the title, sorry.....

 

[bracconiere]

I don't take malt batches and such into account, like some here do.

if that's a jab at me, i'm still learning! i have to!

(if i get 75% with one batch, and 85% with another from the same bag of barley, it's something to look into! )

 

[bracconiere]

oh i'll add, if you're fly sparging as it sound, pick up a refractometer for runoff readings, and they say to stop at 1.012...(i think?)

but any way someone is going to ask what effec your're talking about and you'll need a refrac for lature effec and mash effec answers,

 

[bracconiere]

well @Plastic Brewkettle , someone else that speaks straight will have to chime in on this...but we whent from thinking you were supreme vorlaufing, to now i'm thinking your 'trying' to do a fly sparge but draining the mash tun, and then just slowly fly sparging with no water in it?

 

[Plastic Brewkettle]

@jrgtr42 I'm off by .008 to .022. Readings are taken after boil. From what I'm reading here, I've been sparging completely wrong. The books aren't really clear on this stuff.

 

[Beermeister32]

Check the gap on your grain mill. Most people use a credit card thickness gap. If you don't want to adjust it, run your grist through it twice.

Some home brew shops sell pre-ground grist. Their gap may be off.

 

[bwible]

Where are you getting your recipes and figuring your numbers? Everybody’s “system” is different, whether you are a traditional 3 vessel brewer, doing Brew in a Bag, using an electric all in one system or a hybrid of different systems. You have to get to know your system and what to expect. You have to account for all your grain and all your water. There are several brewing software packages available. Using one is highly recommended.

You will have losses that are built into the process along the way. You lose some water that is absorbed by your grain. You lose water that will boiled off. You will lose some water in your mash tun’s “dead space”. You will lose some wort in the kettle that will be left behind with the trub and left over hop matter. You will then lose some more at the end to the yeast waste and sludge that will be left in the bottom of your fermenter after fermentation is complete. You have to account for all of these losses.

Then there is the question of how you are measuring gravity, how are you reading the hydrometer and if you are taking hydrometer calibration and temperature adjustment into account.

The basics go like this:
Let’s say you have a 5 gallon recipe with 12 pounds of grain. First, I would calculate the recipe as a little more than 5 gallons, let’s say at least 5.25 gallons that you want to end up with post boil to account for fermenter losses so that you actually end up with 5 gallons of finished beer when all is said and done. After you have your recipe you total up the amount of grain. Let’s say it’s 12 pounds.

I almost always mash in with 1.5 quarts per pound. Some people do different and will use a thicker or thinner mash. So 12 pounds times 1.5 quarts = 18 quarts or 4.5 gallons mash in. Then you figure your water loss to grains. Its generally a pint per pound, or that is what it works out to in my system. 12 pints = 6 quarts. So you mashed in with 18 quarts and you expect to lose 6 of those to grain absorbtion. That means you can expect to run off 12 quarts. Now you have to know your boil off rate. With my kettle I boil off .5 gallon during an hour boil. Now I have to account for that. If my recipe is for 5.25 gallons at the end, that’s 21 quarts plus 2 for boil off, so I need to collect 23 quarts. Now if you also have significant dead space in your mash tun, you need to add that here too. I will add one more quart to account for junk left behind in the kettle and say I want to collect 24 quarts. I previously figured I have 12 quarts to run off. So I need to have 12 quarts sparge water or 3 gallons. I will collect 24 quarts, 2 will be boiled off during the hour boil with hops, I will lose one quart that will be left behind with junk in the kettle and 21 quarts or 5.25 will go into my fermenter.

When you get your volumes right on a couple batches then you can get a pretty good guess what your efficiency actually is and start creating your recipes based on that.

You can also take a gravity reading when you have all the wort in the kettle. Remember to adjust your reading for temperature and hydrometer calibration. Your hydrometer should say on it or in the packaging somewhere what temperature it is calibrated at. Then there’s a chart in the package or you can use utilities off websites like Brewer’s Friend to enter your reading and wort temperature and get the correction.

You can get an idea what your final gravity reading will be. Its all gravity points and volume. Let’s say I collect 6 gallons at 1.045. 6 x 45 means I have 270 points. If I boil off .5 gallon of water none of those points go away. So for 5.5 it would just be 270 / 5.5 = 49. So I can figure starting with 6 gallons at 1.045 after an hour boil and boiling off .5 gallon I should be left with 5.5 gallons at 1.049.

Hope some of this helps

[edit] long post edited for typos made on my iphone’s tiny screen and keyboard

 

[bwible]

The process of recirculating some of the wort back through the grain bed is called vorlauf. I suppose it might aid efficiency slightly but the real purpose of doing that is to clear your wort. Recirculating back through the grain is using the grain bed as a filter to strain out suspended matter that would leave your wort cloudy. Yes, this process can take awhile. I have an electric all in one and I recirculate with a pump during my entire mash.

 

[bwible]

Another thing to really pay attention to is stirring/mixing the grain with the water really really really well when you mash in. Dough balls will be left in the mash if it is not mixed really well. Dry pockets of grain that don’t get touched by any water will kill your efficiency. You can look for these when you are emptying the grain out of your mash tun at the end

 

[bwible]

These are some useful utilities I use all the time:

ABV calculator:
https://www.brewersfriend.com/abv-calculator/
Hydrometer Temp Correction calculator:
https://www.brewersfriend.com/hydrometer-temp/
Beer Priming Sugar Calculator:
https://www.brewersfriend.com/beer-priming-calculator/

 

[bracconiere]

@jrgtr42 I'm off by .008 to .022. Readings are taken after boil. From what I'm reading here, I've been sparging completely wrong. The books aren't really clear on this stuff.

.008 isn't "TOO" bad....022 would suck donkey balls....


When is next brewday? and be sure to keep us posted on the results of our efforts.

i remember when i used to get 62% effec, in my case i didn't know i was supposed to sparge slowly. the internet tought me that, and i went from my abismial 62% to 83% just like...


hope the internet does the same for you!

 

[Plastic Brewkettle]

@bracconiere Next brew day won't be for a month or so. All my bottles and kegs are full. I will be using some of this stuff. Like I said, the book I have is unclear on exactly how to sparge. I think I know now.

 

[TyYoda]

Best thing I ever did was start using a brewing software and learned how to use it (this is important) . I use Beersmith 3.

Now a lot of folks use Brewfather. BS3 prints out a brew day recipe and has places for you to record all the bits of data you need to input into the software to know your process efficiencies which will help you hit your numbers in subsequent brews if you use a consistent process from batch to batch. Using brewing software isn't necessary but it feels like you want to start controlling and understanding your brewing results.

It's a lot of fun knowing I can take any receipe, input it into BS3 and the software will predict what I will get for results. Additionally, the software will scale any of my recipes to different brew volumes or to a higher or lower ABV. Lots of control to adjust your recipes and amazing accurate.

To be honest, I'm learning to chill over not hitting numbers perfectly. The beer seems to taste the same even if I miss my targets. I would focus more on using repeatable processes which will in turn lead to more predictable results and along the way enjoy.

The biggest improvement on the quality of my brewing was fermentation temperature control and focus on minimizing cold side oxidation.

Good luck in your journey.

 

[bracconiere]

Next brew day won't be for a month or so.

sometimes i forget about real life! i'm betting a 80%! all bets welcome!

 

[jrgtr42]

if that's a jab at me, i'm still learning! i have to!

(if i get 75% with one batch, and 85% with another from the same bag of barley, it's something to look into! )

Not you in particular - but ther's a few I've seen that do. Yeah, off the same bag, if you're getting that wide a difference, it's something to look at.

@jrgtr42 I'm off by .008 to .022. Readings are taken after boil. From what I'm reading here, I've been sparging completely wrong. The books aren't really clear on this stuff.

.008 is close enough to the margin of error I wouldn't worry too much about it.
.022 is pretty far off. You're not really wrong in sparging how you are - fly sparging does that, slowly running off wort by replacing it with water from above, and you want to have some above the grain bed. In theory you keep tabs on your gravity when sparging, and stop when you are somewhere around 1.008, I think - it's been a while since I read up on this. Also in teory, you'll have your pre-boil amount spot on at that point.
Personally I batch sparge - it's way easier and I didn't find a measureable difference in the beer at the end. In this case, run off everything in the mash, and you can do it s fast as you want, rather than spending an hour fly sparging.
Then add in the second strike water addition, stir it in, and let it sit around 15 minutes. Then run that off and Bob's your uncle. I will start heating the first runnings while the batch is sitting, and if I time it right, it's as hot as it'll get before boil when I add the second runnings. That minimizes time for the whole thing to come to a boil.

 

[hotbeer]

I didn't see that you addressed @Sam_92 's question of how much you put in the fermenter.

If you are boiling 7.5 gallons for an hour, then most of us will have 6.5 to 6.0 gallons left at the end. So if the recipe was planning on 5 gallons going into the fermenter, it was probably thinking there'd be more boil off or you are misunderstanding how much water it's asking you to use.

In the short.... too much water for the amount of grain used will leave you with a lower SG.

OG is typically the SG of the wort going into the fermenter after the boil.


There are also some methods and just getting more experienced at mashing and sparging that will allow you to get more sugars from a fixed amount of grain. So poor sparging techniques could be an issue too. But I'd suspect just not enough water boiled off or too much used to get to the kettle.

 

[bracconiere]

You're not really wrong in sparging how you are - fly sparging does that, slowly running off wort by replacing it with water from above, and you want to have some above the grain bed.

 

[RM-MN]

Then add in the second strike water addition, stir it in, and let it sit around 15 minutes.

When batch sparging there is no need to wait. Stir the cool (doesn't need to be heated) into the grains as soon as they have been drained. Stir well to get the sugars separated from the grain, then drain.

 

[Plastic Brewkettle]

@hotbeer I'm putting 5 gallons in the fermenter. I tried a 6.5 down to 5.5 (or so) gallon boil a batch or so ago and still had low OG numbers.
@jrgtr42 I may try batch sparging next time.

 

[jrgtr42]

When batch sparging there is no need to wait. Stir the cool (doesn't need to be heated) into the grains as soon as they have been drained. Stir well to get the sugars separated from the grain, then drain.

See, I've always read to have the water at mash-out temps, and allow to sit for a little bit to get the most out of the mash.

 

[day_trippr]

That would be misinterpreting the point of the high temperature "mash out" - which is simply to kill ("denature") the saccharification enzymes extant so as to "fix" the fermentability character of the wort...

Cheers!

 

[bracconiere]

That would be misinterpreting the point of the high temperature "mash out" - which is simply to kill ("denature") the saccharification enzymes extant so as to "fix" the fermentability character of the wort...

Cheers!

@Plastic Brewkettle , obviously is set up for fly sparging if he has a HLT, sparge arm...and just needs to keep the level above the surface....to prevent "pitting" in the grain!

the point of a sparge arm for fly sparging is to keep the water ABOVE the surface, while not drilling holes in the grain bed...

 

[RM-MN]

@hotbeer I'm putting 5 gallons in the fermenter. I tried a 6.5 down to 5.5 (or so) gallon boil a batch or so ago and still had low OG numbers.
@jrgtr42 I may try batch sparging next time.

There are only a few causes of getting low OG if you have the right amount of grain. A bad sparge can be one of those things but the most common is a poor crush. If the water can't get to the starches and activate the enzymes, you don't get all the starches converted to sugars. Then some of the sugars that do get converted may not leach out of the grain particles. A conventional mash tun requires a compromise between good conversion and being able to drain the mash tun. Too fine of a crush and the grain husks are shredded so they won't form the filter bed. Too coarse of a crush and you get poor conversion. Most LHBS would rather sell you more grain to achieve the expected OG than to risk customers being mad because they get a stuck mash.