Starch Conversion

[CleverBeerPun]

Hello,

I brewed a blonde ale yesterday, and my mash temp was 9 degrees below the target 150. At the sixty minute mark I had a positive iodine test so I let the mash sit for another 75 minutes. At the end of the second wait period I again had a positive iodine test. So, I decided to move forward with the sparge and just accept that my beer would likely be much drier than expected. At the end of the sparge I decided to perform another iodine test and this time the test was negative. My pre-boil O.G was 1.028 - lower than the 1.034 Beersmith calculated.

TL;DR - Should I be hopeful of the final sugar-profile of the mash given that I did finally get a negative iodine test result at the end of sparging?

 

[TheMadKing]

You likely had a mash temp that was so cool that you had little fermentable sugar produced at all. However, if you used hotter sparge water, you may have had conversion occurring during your sparge, so it's really hard to say. What was your actual OG? (post boil)

 

[CleverBeerPun]

My post boil OG was 1.052 but Beersmith says it should have been 1.036.
I scaled this recipe (https://www.homebrewtalk.com/showthread.php?t=42841) down to 5 gal batch size.

I performed a single infusion of 2.5 gallons and divided my batch sparge water into 3 steps, total sparge volume was 4 gallons (I ended up collecting 5 gallons in the boil kettle before using the final quart of sparge water).
Also, the boil was 60 minutes.

 

[TheMadKing]

My post boil OG was 1.052 but Beersmith says it should have been 1.036.
I scaled this recipe (https://www.homebrewtalk.com/showthread.php?t=42841) down to 5 gal batch size.

I performed a single infusion of 2.5 gallons and divided my batch sparge water into 3 steps, total sparge volume was 4 gallons (I ended up collecting 5 gallons in the boil kettle before using the final quart of sparge water).
Also, the boil was 60 minutes.

That doesn't really add up... I think you must either have a measurement error or a bad input into beer smith. Your preboil gravity should always be way lower than your post boil gravity. Not the .002 beersmith was saying.

Did you measure the gravity of hot wort? Hydrometers only work at their calibrated temp, which is usually 68 degrees. Temperature compensation formulas are pretty inaccurate too.

Make sure to double check all your beersmith numbers and look for mistakes in your inputs or volumes.

Can you post your exact recipe too? I've had issues with the way beersmith scales recipes.

 

[jrcrilly]

If you had the boil time properly entered, there is no way that Beersmith would predict 1.034 preboil and 1.036 postboil. That would indicate very nearly zero boiloff. What were your actual pre- and post- boil volumes?

 

[CleverBeerPun]

Thanks for all of the feedback!
I made sure to cool both gravity samples to 60F (whats printed on my hydrometer) via my kegerator prior to measuring.
I think I may have a fundamental misunderstanding here - I thought post boil OG would always be higher than pre - loss of liquid but retention of solids.
Here is the recipe:

6.38 lbs 2 row
.68 lbs dextrine
.46 lbs crystal 10L
.46 Vienna

.23 oz centennial (55 mins)
.23 oz centennial (35 mins)
.23 oz cascade (20 mins)
.23 oz cascade (5 mins)

1 pkg Nottingham dry yeast (1L yeast starter made 48 hrs prior to pitching)

mash: 2.5 gal water @ 150F (was really 141F b/c i messed up) for 60 mins
sparge: 4 gal @150 (this temp. i did hit exactly)

the pre-boil volume i measured exactly as 5 gal, the post boil vol i didn't. (what measurement technique do people normally use for this? check it once its transferred to the carboy?)

again, thanks for all of the advice!

 

[TheMadKing]

Thanks for all of the feedback!
I made sure to cool both gravity samples to 60F (whats printed on my hydrometer) via my kegerator prior to measuring.
I think I may have a fundamental misunderstanding here - I thought post boil OG would always be higher than pre - loss of liquid but retention of solids.
Here is the recipe:

6.38 lbs 2 row
.68 lbs dextrine
.46 lbs crystal 10L
.46 Vienna

.23 oz centennial (55 mins)
.23 oz centennial (35 mins)
.23 oz cascade (20 mins)
.23 oz cascade (5 mins)

1 pkg Nottingham dry yeast (1L yeast starter made 48 hrs prior to pitching)

mash: 2.5 gal water @ 150F (was really 141F b/c i messed up) for 60 mins
sparge: 4 gal @150 (this temp. i did hit exactly)

the pre-boil volume i measured exactly as 5 gal, the post boil vol i didn't. (what measurement technique do people normally use for this? check it once its transferred to the carboy?)

again, thanks for all of the advice!

EDIT: I typed wrong when I posted earlier, sorry about that! I fixed it haha

You are understanding correctly, but your terminology is a bit off.. Original gravity refers only to the specific gravity reading taken post boil. Any other reading is just called a specific gravity reading, except for the final gravity which is post fermentation. Minor point though.

The issue is that your post boil gravity should be waaay more than your pre boil gravity.. Like 1.032 should end up closer to 1.050. Which is what you actually saw. So the fact that beersmith is telling you 2 points different means you have something set up wrong in there.

Most folks have graduated markings on their boil kettle, or in their fermenter for measuring volume. You can use a pitcher to add specific volumes of water and put paint marks on the outside.

Without actually running your numbers, that amount of grain looks like a1.05-ish beer for a 5 gallon batch.

What was your intended batch size?.. 5 gallons pre boil (and always boil with the lid off, which I strongly suspect you didn't) should yield about 3.5 gallons post boil, or somewhere in that neighborhood.

Without measuring both your volumes AND your specific gravities accurately you can't calculate efficiency.

As far as conversion goes, I think you might be ok because of your sparhe water being 150.. You essentially just did an extended protein rest which shouldn't hurt anything.

I think you'll be fine, just let it ferment and see how it tastes! You might have an off flavor if you boiled with the lid on though. DMS is a compound that's normally driven off in the boil, and it tastes like cooked corn.

Only thing you can do now is be patient and wait it out. Good luck!

 

[CleverBeerPun]

@TheMadKing - thanks for the detailed explanation!

I understand now, and luckily i do boil with the lid off. Ill have to play with the beersmith setup to see why its not making sense with respect to gravities. Also, I'll be sure to add some graduation markings on the kettle and carboy, the devil is in the details and I haven't been dilligent about capturing volume changes throughout the process.

Again - thats for all the advice, I'm eager to see how the batch turns out!