Mash temp vs OG - Guidance please

Hi,

We have not been hitting our OG as expected and would like some input. My understanding is that at the lower range of the mash temp, you will get a higher OG then at the higher range of the mash temp. We are ussually a couple of points off our intended OG.

On the other side, to obtain the correct FG requires a combination well aerated wort along with the yeast.

Please shed some light on this for us.

Thanks,

Eric

I don't believe that mash temps will affect Original Gravity.

With a higher mash temp the wort will contain more complex sugars and dextrins.  A lower mash temp will produce more simple sugars and in turn will be more fermentable.

Same gravity just a different composition of sugar types.

The biggest thing that changed my efficiency is grain crush.  Crushing my own grain yielded about 10% better efficiency.

If you're efficiency is already in an acceptable range, just tweak your efficiency in beersmith and use a little bit more grain and you'll start hitting it right on.

Thanks. We crush our on grain but our numbers are not were I want the. So do you thing we need more grain to hit our numbers?

That may be it.  If you're getting a consistent efficiency that's in an acceptable range then taking this into account when formulating or scaling a recipe will help you get where you want to go.

Check out Brad's blog post on efficiency-
http://www.beersmith.com/blog/2008/10/26/brewhouse-efficiency-for-all-grain-beer-brewing/

noodle said:

Thanks. We crush our on grain but our numbers are not were I want the. So do you thing we need more grain to hit our numbers?

Click to expand...

That is one way to get there.  But what is your efficiency today?  If it is 60%, then you could likely get 10% to 15% more efficient and use less grain.  I compared efficiency to a friend recently as your MPG, and both a Prius and a Hummer can make the same trip, but using different amounts of fuel.  Grain is the fuel. 

I'd first recommend taking accurate measurements and determining your current efficiency.  If it is maxed out for your system, then you must use more grain. 

Just read "5 ways to improve your efficiency" and have a question about this -

Sparge Slowly
Most beginners attempt to sparge their mash much too fast. Sparging too quickly leaves insufficient time for the hot water to extract the sugars in the grain bed. Limit the flow out of your mash tun to just above a trickle. It should take 30-50 minutes to fully sparge a 5 gallon all grain batch (about 6 gallons of wort).


We sparge a 20 gallon batch in 60 minutes and always have with good results. A can't imagine that it should take 4 hours to sparge 20 gallons.

The only thing we changed from last season was our base malt. We switched from Muntons Pale 2 row to MaltEurop 2 row.

I'm wondering if this is our issue.

Thanks,

Eric

Have you figured out what your efficiency was for this batch?  That would be a great place to start.

Ok, Here is what I have for comparison between batches.

Octoberfest 1st batch Sept 17, 2010 - Malteurop

Est OG = 1.067
Act OG = 1.057

Est FG = 1.016
Act FG = 1.015

5.48%

Eff = 64.24%

Octoberfest 1st batch Sept 26, 2010 - Malteurop

Est OG = 1.066
Act OG = 1.060

Est FG = 1.016
Act FG = 1.014

6.0%

Eff = 67.69%

Porter 1st batch March 21, 2010 - Muntons

Est OG = 1.048
Act OG = 1.053

Est FG = 1.012
Act FG = 1.013

5.21%

Eff = 83.40%

Porter 1st batch Oct 24, 2010 - Malteurop

Est OG = 1.056
Act OG = 1.051

Est FG = 1.014
Act FG = 1.018

4.3%

Eff = 67.81%


Please explain what may be happening. We mash at 156-158 (1 hour) and sparge at 168-170 (1 hour).

Thanks,

Eric

Are you taking into account the volume of wort that you're collecting?  You have to take that into account when figuring efficiency.

I like to take volume and gravity measurements right out of the mash tun to figure efficiency.  This cuts out any other losses and gives the most accurate measurement.

Volume into boiler is 23.16 gallons according to the software and should be fairly close to actual volume prior to boil. Actual OG is measured after boil. I don't measure OG into boiler.

Eric

Efficeincy of last 7 batches as follows:

Octoberfest = 64.24%
Octoberfest = 67.69%
Brown = 71.82%
Pub = 72.56%
Porter = 67.81%
ESB = 68.83%
Chocolate Oatmeal Stout = 73.02%


Why am I getting this variation in efficiency?

Thanks,

Eric

noodle said:

Volume into boiler is 23.16 gallons according to the software and should be fairly close to actual volume prior to boil. Actual OG is measured after boil. I don't measure OG into boiler.

Eric

Click to expand...

In general terms, total efficiency consists of mash efficiency and lautering efficiency.  Or, how well you mashed/converted (compared to the lab), and how well you extracted from the grain whatever it was that you converted.  I think you must measure your OG going into the boiler in order to determine your efficiency. 

Each brewer estimates their efficiency, enters that into software, software calculates grain to use to make that beer.  As we learn our systems, we learn the EE% number to use.  With practice, we learn to hit it.

If you are measuring OG only after boiling, then you are inserting the evaporation factor into it, plus the accurate measurement of the volume after the boil.  (If you don't measure SG pre-boil, then you also cannot be calculating your change from pre-boil SG to post-boil SG; knowing this change helps determine your evap rate, another important aspect of hitting target OGs.)

Efficiency thus can only be measured at the moment wort collection stops, when you measure total volume collected at what SG.  Then compare your results to the plan. 

Specific to these four batches, the Muntons batch had a different malt, and it was the lowest target OG beer.  I think your system is fairly consistent and you just need to work on measurements to enter into BeerSmith so that your estimates and targets tighten up a bit. 

Thanks for the info. Regarding total volume and measuring OG into the boil, Are you just dropping your hydrometer into the kettle or drawing some off to check? I assume that you use the software to correct for temp. Is it safe to drop the hydrometer into the kettle at such a high temp?

Thanks,

Eric

You should not drop the hydrometer into the hot wort.  You run a real risk of shattering it in the kettle.  You should draw some off into the same tube, and chill it to 60f.  I keep a 2qt pan in the freezer and pour the wort into that and swirl it around then back in the freezer for a couple minutes until 60f.  While you can calculate for temp variation, it is best to measure it 60f. 

Be sure to stir the wort before taking a sample.  You want to be sure you are getting an good sample.  I find that sampling unstirred can vary 2 to 4 points.  Brau Kaiser http://braukaiser.com/wiki/index.php/Main_Page has some  great information but is pretty technical.  Still, if you want soem good information on mashing and efficiency, check it out.

Each grain has a potential extract value.  This might be different than the grain you select in Beersmith.  For the most accurate estimation of potential extract, you would need to ensure the grains you use have the correct values in Beersmith.  Different maltsters have different values.  While they may be small, the the larger the amount of grain, the more affect it has.  For example, I have about 10 pale malts in beer smith.  They range of 1.035 to 1.038 in potential starting gravity.

jomebrew said:

You should not drop the hydrometer into the hot wort. 

Click to expand...

Ditto.  Likely dangerous.

jomebrew said:

I keep a 2qt pan in the freezer and pour the wort into that and swirl it around then back in the freezer for a couple minutes until 60f. 

Click to expand...

This is brilliant for hydrometer use.  I use a refractometer during brew day b/c it's quick and easy.  I use the long spoon to put a few drizzles into some s/s condiment cups (WMT, $1 for four).  When it cools down, I put on refractometer to get a quick read on the SG. 

Today, in fact, I noticed that my boil down/evap was higher than expected, so I added a pint of boiling water at five minutes, and hit the target SG exactly.