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My OG is a little low every time

I have brewed my 4th all grain recipe today and I noticed that my OG is a little lower than it should be - which is what normally happens. I know that it is not a big deal - the beer will still be wonderful but I am an analytical person and I would like to know why this continues to happen.

The beer I made today is the Oktoverfest and it is supposed to be 1058 and it ended up at 1052. This seems to be the norm - if the OG should be above 1055, I seem to be 6 to 10 points too low.

What are some of the factors that can make my OG end up low?

I was hoping that it would be perfect today because I came up with exactly 5 gallons of wort from the kettle before it stopped flowing from the vlave. i looked in the kettle and the wort that was still in there was ‘sludgy’ so i would not have wanted it in my carboy.

Thank you for anything ideas that you can give me.

Jon

Grain crush is the biggest factory for efficiency. How’s your crush look? If you have your own mill set the gap closer if not run it through the mill twice at your LHBS.

Or you boil off more than you think therefore concentrating your wort.

just lower your efficiency number in your recipe calculator and you should then hit your number.

I use the mill at Northern Brewer - I do not know what they set it at, but I will try running it through twice.

thanks

I have noticed that if I start my boil at 6.5 gallons, I seem to have just enough for 5 gallons in the carboy. If I concentrated the wort, wouldn’t it make the OG higher?

Jon

Yep, sorry, I read your original post wrong. I recommend putting your overall Brewing profile into BeerSmith and tweaking the numbers by looking back at your previous measurements. Once you get it dialed in it works like a charm.

There are numerous factors that can contribute to low mash efficiency- too many to go into in any depth in the span of one post. Someone else here pointed out poor crushing of malt as the single most influential factor. I don’t know if I’d agree that that’s really the #1 biggest factor, but it’s definitely up there in at least the top 3. The other factor that comes immediately to mind for me is temperature control. If the setup you’re using doesn’t guarantee tight control on the temperature of the mash- as in having the ability to sustain a stable temperature with fairly tight tolerances over a long time- that might be your biggest problem. I don’t know what temp you mash at, or what kind of setup you have, but if you think there might be a problem with your system in the area of temperature control, that’s the very first thing I’d try to fix.
Another big area of concern with respect to mash efficiency is hitting the proper pH range of your mash. You’ll hear a few people out there tell you that they don’t bother messing around with mineral additions in their brewing water, or with monitoring mash pH. But I’m here to tell you that it’s really a critical area of concern, and if you haven’t taken the time to get at least a perfunctory understanding of mash chemistry, you really need to. It’s not as daunting an area of research as you might think it is, either. You can go out and buy whole books on the subjects of brewing water chemistry if you want to, but you don’t have to. There are plenty of concise sources of information on the subject available on the web, and even free brewing software programs that you can download that will make it easy to design target water profiles for different styles of beer using simple mineral additions.
Anyway, I don’t want to go on forever :cheers:

[quote=“deliusism1”]There are numerous factors that can contribute to low mash efficiency- too many to go into in any depth in the span of one post. Someone else here pointed out poor crushing of malt as the single most influential factor. I don’t know if I’d agree that that’s really the #1 biggest factor, but it’s definitely up there in at least the top 3. The other factor that comes immediately to mind for me is temperature control. If the setup you’re using doesn’t guarantee tight control on the temperature of the mash- as in having the ability to sustain a stable temperature with fairly tight tolerances over a long time- that might be your biggest problem. I don’t know what temp you mash at, or what kind of setup you have, but if you think there might be a problem with your system in the area of temperature control, that’s the very first thing I’d try to fix.
Another big area of concern with respect to mash efficiency is hitting the proper pH range of your mash. You’ll hear a few people out there tell you that they don’t bother messing around with mineral additions in their brewing water, or with monitoring mash pH. But I’m here to tell you that it’s really a critical area of concern, and if you haven’t taken the time to get at least a perfunctory understanding of mash chemistry, you really need to. It’s not as daunting an area of research as you might think it is, either. You can go out and buy whole books on the subjects of brewing water chemistry if you want to, but you don’t have to. There are plenty of concise sources of information on the subject available on the web, and even free brewing software programs that you can download that will make it easy to design target water profiles for different styles of beer using simple mineral additions.
Anyway, I don’t want to go on forever :cheers: [/quote]

You may have hit the nail on the head with the temperature control. I use a cooler for this and i do lose about 4.5 degrees over the course of the hour. I also did not start at the correct temp today - it wanted 152 and I was at 150.5. So it could have been the combo of the two that dropped my OG?

I have read online where somebody had the exact same cooler I have and they bought a can of spray insulation and insulated the cooler. Perhaps that will be on my list of upgrades.

Jon

I had a related issue of not hitting final gravity. Turns out my hydrometer was off by .005; prolly not the issue here, but worth checking to make sure your measuring equipment is properly calibrated (hydrometer or refractometer). As they say in my line of work, sometimes no data is better than bad data!

you said you are consistently hitting the same number of points different than intended. that is actually good because that shows consistency. By lowering the efficiency number in your calculator you will only have to compensate by adding a few more ounces of grain to hit your number. consistency is more important than efficiency, it only costs a few more pennies in extra grain.

[quote=“gusrotteyman”][quote=“deliusism1”]There are numerous factors that can contribute to low mash efficiency- too many to go into in any depth in the span of one post. Someone else here pointed out poor crushing of malt as the single most influential factor. I don’t know if I’d agree that that’s really the #1 biggest factor, but it’s definitely up there in at least the top 3. The other factor that comes immediately to mind for me is temperature control. If the setup you’re using doesn’t guarantee tight control on the temperature of the mash- as in having the ability to sustain a stable temperature with fairly tight tolerances over a long time- that might be your biggest problem. I don’t know what temp you mash at, or what kind of setup you have, but if you think there might be a problem with your system in the area of temperature control, that’s the very first thing I’d try to fix.
Another big area of concern with respect to mash efficiency is hitting the proper pH range of your mash. You’ll hear a few people out there tell you that they don’t bother messing around with mineral additions in their brewing water, or with monitoring mash pH. But I’m here to tell you that it’s really a critical area of concern, and if you haven’t taken the time to get at least a perfunctory understanding of mash chemistry, you really need to. It’s not as daunting an area of research as you might think it is, either. You can go out and buy whole books on the subjects of brewing water chemistry if you want to, but you don’t have to. There are plenty of concise sources of information on the subject available on the web, and even free brewing software programs that you can download that will make it easy to design target water profiles for different styles of beer using simple mineral additions.
Anyway, I don’t want to go on forever :cheers: [/quote]

You may have hit the nail on the head with the temperature control. I use a cooler for this and i do lose about 4.5 degrees over the course of the hour. I also did not start at the correct temp today - it wanted 152 and I was at 150.5. So it could have been the combo of the two that dropped my OG?

I have read online where somebody had the exact same cooler I have and they bought a can of spray insulation and insulated the cooler. Perhaps that will be on my list of upgrades.

Jon[/quote]
Temperature of the mash has a big impact on fermentability, which affects FG, but unless it is WAY WAY off it has very little impact on conversion, which impacts OG. I doubt that is what is causing the problem for you. As deliusism1 stated, pH can also impact conversion, but the effects from that will vary from grain bill to grain bill, and if you are brewing different types of beers you would not be getting the same consistency of the effect due to pH.

I think gdtechvw is exactly right; the crush is the culprit. But rather than trying to change that, just follow Sonex’s advice and plug your past results into Beersmith or some similar brewing program to calculate what your system efficiency is, then just design your recipes using that. You will be spot on for the future.

Jon[/quote]
Temperature of the mash has a big impact on fermentability, which affects FG, but unless it is WAY WAY off it has very little impact on conversion, which impacts OG. I doubt that is what is causing the problem for you. As deliusism1 stated, pH can also impact conversion, but the effects from that will vary from grain bill to grain bill, and if you are brewing different types of beers you would not be getting the same consistency of the effect due to pH.

I think gdtechvw is exactly right; the crush is the culprit. But rather than trying to change that, just follow Sonex’s advice and plug your past results into Beersmith or some similar brewing program to calculate what your system efficiency is, then just design your recipes using that. You will be spot on for the future.[/quote]

+1. Crush is usually the biggest culprit. Agreeing with rebuiltcellars, temperature could contribute some, but being off a few degrees won’t effect OG, at least not as much as you’re talking. It WILL effect your FG, making the wort more or less fermentable. Don’t get me wrong, nailing your mash temps is critical, but I don’t think that’s the issue with your efficiency. If you are always low by about the same amount, you always get your grain crushed at the same place… I’m saying crush. It’s the most logical and easiest to fix. Have your grain double crushed next time and see what you get.

Any chance your volume markings are off? Maybe what’s marked 5 gallons is slightly more?

I think step one is to figure out what efficiency you are getting since its consistent. You can then base your recipes around that or start looking at way to improve you efficiency if you want. Crush, losses in kettle +mash tun , conversion issues etc…

I’ve gotten pretty much dead on 70% brew house efficiency since I started all grain brewing 30 batches now. 70% is average not horrible not the best but its always 70% and that’s what’s really important. Factoring in 70% efficiency Ill hit my OG dead on usually +/- a point or two at the most.

http://braukaiser.com/wiki/index.php?ti ... Efficiency

This May help also, at least it helped me.

[quote=“gusrotteyman”][quote=“deliusism1”]There are numerous factors that can contribute to low mash efficiency- too many to go into in any depth in the span of one post. Someone else here pointed out poor crushing of malt as the single most influential factor. I don’t know if I’d agree that that’s really the #1 biggest factor, but it’s definitely up there in at least the top 3. The other factor that comes immediately to mind for me is temperature control. If the setup you’re using doesn’t guarantee tight control on the temperature of the mash- as in having the ability to sustain a stable temperature with fairly tight tolerances over a long time- that might be your biggest problem. I don’t know what temp you mash at, or what kind of setup you have, but if you think there might be a problem with your system in the area of temperature control, that’s the very first thing I’d try to fix.
Another big area of concern with respect to mash efficiency is hitting the proper pH range of your mash. You’ll hear a few people out there tell you that they don’t bother messing around with mineral additions in their brewing water, or with monitoring mash pH. But I’m here to tell you that it’s really a critical area of concern, and if you haven’t taken the time to get at least a perfunctory understanding of mash chemistry, you really need to. It’s not as daunting an area of research as you might think it is, either. You can go out and buy whole books on the subjects of brewing water chemistry if you want to, but you don’t have to. There are plenty of concise sources of information on the subject available on the web, and even free brewing software programs that you can download that will make it easy to design target water profiles for different styles of beer using simple mineral additions.
Anyway, I don’t want to go on forever :cheers: [/quote]

You may have hit the nail on the head with the temperature control. I use a cooler for this and i do lose about 4.5 degrees over the course of the hour. I also did not start at the correct temp today - it wanted 152 and I was at 150.5. So it could have been the combo of the two that dropped my OG?

I have read online where somebody had the exact same cooler I have and they bought a can of spray insulation and insulated the cooler. Perhaps that will be on my list of upgrades.

Jon[/quote]
Actually, if you started at 150.5 degrees F and ended up around 146, you would still be in the beta amylase range, which is the optimal range to maximize the potential extract of the wort. So I’d rule out temp control as the number one suspect (although I will say that 4 or 5 degrees is a little bit too much to lose in an hour for an insulated cooler). I’m thinking it’s either your mash pH or the fineness of the crush on the grains, or both. I’d attack both of those areas to make sure you’re doing everything you can to make the most out of your beer.

I use this efficiency calculator.

http://www.brewersfriend.com/brewhouse-efficiency/

Could also be your lautering; if you’re batch sparging, you’re going to lose efficiency to the benefit of huge time savings.

I use the mill at Northern Brewer - I do not know what they set it at, but I will try running it through twice.

thanks[/quote]

If you use the mills at Northern Brewer in Saint Paul (and probably Minneapolis, but I don’t know for sure), the two mills in the grain room are set at very different settings. I just noticed this myself. The mill closer to the street was set REALLY tight… like .02 and the mill farther from the street was set at like .04.

I typically use the .04 mill, but for my last brew used the .02… and my efficiency was way higher. I was shooting for an OG of 1.060 and ended at 1.070.

My guess is the crush.

The mill at N.B. Minneapolis is set to .04. I was consistently getting poor efficiency, even with a double crush. A guy showed me a trick a few months ago that if you “trickle” the grains onto the roller rather than dumping them on into the hopper your get a much better crush. It takes a little more time but that got me to 78% from low 60’s.
The next thing that bumped it up even more was adjusting mash and sparge ph. My last 2 batches got me to 82% I didn’t realize how alkaline my water was.

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