Rye fermentation yield

[klattig]

Hi All, 

We make a Rye whiskey with 10% wheat, 5% cararye, and 85% malted rye.  We love the flavor, but consistently fail to ferment to completion - FG is usually 1.007-1.008.  We do ferment to completion with several other mashbills (all-corn, bourbons, 4-grain whiskey, etc); we only struggle with Rye.  Our mash process looks like this:

 - wheat in with JZyme TAA (high temp alpha) at 175 for an hour

 - cool to 155; add cararye & malted Rye along with JZyme SGA (saccharification enzyme).  Hold at about 150 for 1hour. 

 - Cool to 85F, pitch yeast.

We run a fairly thick mash so our brix at yeast-pitch is 17-19, and ferment / distill on-grain so we don't worry about viscosity / lautering yield.  We maintain ferment pH between 4.5 & 3.8 (usually no intervention is needed). We've played with ferment temps, ranging from 90F to 82F doesn't seem to matter.  We played with adding yeast nutrients, with no effect.  Adjusting the saccharification hold time (up to 2.5 hours) & temp (145-160F) has no effect.  In all cases, the mash ferments very fast, but reaches 1.007-8 in about 60 hours then stops.   

Any suggestions for how we can squeeze the last 1-2% ethanol yield from our ferment?

Thanks!

[indyspirits]

19 brix is what... 1080?  I'd consider dropping your gravity to around 1050. Should ferment dry and much quicker.  I've always found high gravity ferments to be persnickety in terms of going dry.  I assume JZyme SGA is some type of glucoamylase which snips long chain dextrines into fermentable sugars?

 

 

[klattig]

48 minutes ago, indyspirits said:

19 brix is what... 1080?  I'd consider dropping your gravity to around 1050. Should ferment dry and much quicker.  I've always found high gravity ferments to be persnickety in terms of going dry.  I assume JZyme SGA is some type of glucoamylase which snips long chain dextrines into fermentable sugars?

 

 

Yes, I agree 1080 is high - but we start all our whiskies in this range with no problems.   It's been a year ago, and our process & enzyme regime was different, but we tried about 15brix OG with the same result.  

The datasheet for the SGA says it's a "Saccharifying glucoamylase (or amyloglucosidase)."

It seems like we're missing something fundamental about fermenting rye malt...

[PeteB]

The final gravity reading is not measuring sugars only. It is measuring all sorts of soluble compounds. In my experience rye has a lot of dissolved compounds that are not fermentable sugars, and I assume these also have something to do with the high viscosity. 1.008 could be as low as it is possible to go with rye. In my opinion each different grain will have a different original and final gravity. 

[Tom Lenerz]

The cararye is malted to have sugar that is non-fermentable, so your fermentation is probably complete. Most beers with caramel malts finish higher than 1.007. If this is about making alcohol and increasing yield, swap the cararye for something cheaper that converts. If you are happy with the flavor you are getting, note that it probably will have an impact on that.

[klattig]

14 hours ago, PeteB said:

The final gravity reading is not measuring sugars only. It is measuring all sorts of soluble compounds. In my experience rye has a lot of dissolved compounds that are not fermentable sugars, and I assume these also have something to do with the high viscosity. 1.008 could be as low as it is possible to go with rye. In my opinion each different grain will have a different original and final gravity. 

Tom, we don't use a hydrometer for OG or FG - we use a refractometer.  Does your comment also apply to brix readings obtained with a refractometer?  I'm under the impression that longer glucose chains (dextrins) will impact the refractometer, but not so much 'other compounds'.  Thoughts?

[kkbodine]

4 minutes ago, klattig said:

Tom, we don't use a hydrometer for OG or FG - we use a refractometer.  Does your comment also apply to brix readings obtained with a refractometer?  I'm under the impression that longer glucose chains (dextrins) will impact the refractometer, but not so much 'other compounds'.  Thoughts?

You can't correctly measure final gravity with a refractometer; the alcohol distorts the reading. Assuming you mean the reading after fermentation.

[klattig]

3 minutes ago, kkbodine said:

You can't correctly measure final gravity with a refractometer; the alcohol distorts the reading. Assuming you mean the reading after fermentation.

Ah, true - we use a mathematical formula that takes into account the initial reading to compute an approximated gravity.  We got this from the More Beer website (I attached it here - it's cool).

Brix and SG.xls

[Roger]

It's nice to have all these numbers, like OG , FG, OHMY , etc but the real issue is: how much alcohol are you getting, from the total amount of grain (carbohydrate portion)?  

Are you finding a big difference between your various mash bills, or is this particular mash the only one showing less (based on carb content ) ?

 

[Julius]

What is the PG to bushel yield of the stripping run?

[PeteB]

On 11/22/2018 at 2:12 AM, klattig said:

Tom, we don't use a hydrometer for OG or FG - we use a refractometer.  Does your comment also apply to brix readings obtained with a refractometer?  I'm under the impression that longer glucose chains (dextrins) will impact the refractometer, but not so much 'other compounds'.  Thoughts?

A refractometer has the same problems as a hydrometer when trying to measure anything that is not a simple mixture of just 2 compounds.

A refractometer and hydrometer can measure accurately the amount of sugar dissolved in water, or just alcohol plus water, but when you have 2 or more compounds in varying amounts, plus water, they don't measure well.

OG and FG as well as original and final refractometer readings assume that it is only the sugar that has been turned into alcohol, and no other compounds have been altered.

[klattig]

On 11/26/2018 at 10:19 AM, Julius said:

What is the PG to bushel yield of the stripping run?

This is hard to answer with precision, since we recycle some heads & tails in every batch.  I agree it is the key parameter to determine actual efficiency; my best estimate is 75-80 proof gallons stripping yield from 1000# grain.  I'd be interested to hear what others are yeilding...

[ErictheRed]

26 minutes ago, klattig said:

This is hard to answer with precision, since we recycle some heads & tails in every batch.  I agree it is the key parameter to determine actual efficiency; my best estimate is 75-80 proof gallons stripping yield from 1000# grain.  I'd be interested to hear what others are yeilding...

75 to 80 pg stripping run from 1000# grain would be about 4.2-4.4 pg per bushel

I am getting about 4.1 to 4.4 pg per bushel from my stripping runs so it sounds like we are right with your estimates.

  But low wine produced at 4.1 to 4.4 won't produce 5 pg per bushel of grain of high wine, right? Should the high wine targets be 5 pg per bushel?

[klattig]

22 hours ago, ErictheRed said:

75 to 80 pg stripping run from 1000# grain would be about 4.2-4.4 pg per bushel

I am getting about 4.1 to 4.4 pg per bushel from my stripping runs so it sounds like we are right with your estimates.

  But low wine produced at 4.1 to 4.4 won't produce 5 pg per bushel of grain of high wine, right? Should the high wine targets be 5 pg per bushel?

Well, your yield certainly doesn't get better with the second distillation, Eric!  How much you lose depends on how tight your hearts cut is, whether you recycle heads & tails, and if so how much foreshots your throw out & how deep you go into tails...

[johnbsys]

Sounds to me like your pH might be getting too low during the ferment?