GF brew having troubles fermenting, AGAIN!

[Lurpinator]

First off, here is the recipe I created.

GF Mystery (5 gal)

.5 lbs Toasted Buckwheat Groat (Steeped from 100 F until boil)

7 lbs Tapioca Syrup (60 min.)
.5 lbs Dark Brown Sugar (30 min)
.5 lbs Rice Syrup Solids (30 min.)
1 Tbsp Irish Moss (20 min.)
6 oz Molasses (10 min.)

1 oz NZ Cascade Whole (60 min.)
.5 oz NZ Cascade Whole (30 min.)
.5 oz NZ Cascade Whole (5 min.)

2 packets Safale S-04

OG: 1.062
FG: ?

I brewed this a week ago Friday, and took a grav reading yesterday only to find out it has only dropped from 1.062 to 1.045. This happened on my first brew, so after 10 days, I pitched another packet of yeast, and it finished fermenting within another week or so. This time, I pitched 2 packets right at the start to give it a head start, but it is still slow. I think I may know the problem, though. I have a 20L SS pot that I use for about 3 gallon "boils" when I brew. I say "boils" because our stovetop range is so weak, that the batch doesn't really ever boil. There are a couple small bubbles that make their way to the top, but no foam or anything really. I ordered a bayou propane burner this week, so that will help out alot. Anyways, my question is, would this weak boil be contributing to the weak fermentation? And, if so, what can I do to get this batch fermented through because the sample I tasted was SOOOOOO good, I would hate for this to not finish correctly. And, sorry I didn't mean to write a novel here.

 

[Joe Camel]

It looks like you have lots and lots of sugar there, but not a lot of protein, maybe try adding some yeast nutrient to help them along.

 

[oberon567]

For this recipe the weak boil would not affect fermentation - the suagrs are already ready to go, ready to be converted. The boil is not doing anything except dissolving them equally into the solution.

The boil really provides the opportunity for your hops to do their work and for you to boil off some off flavors some malts (like Pilsner) might produce, and of course it is reducing the amount of liquid from your mash to reach your SG. In your case the only thing that applies is the hops.

You dont really need protein to ferment - lots of wines have nothing but sugar in them (see EdWort's Apfelwein as an example, or look up any dandelion wine...). Your OG is not all that high, 1 packet of properly rehydrated S-04 should be fine, and two packets should be extra fine... what temperature are your fermenting at? Is your yeast fresh?

 

[Lurpinator]

It looks like you have lots and lots of sugar there, but not a lot of protein, maybe try adding some yeast nutrient to help them along.

All GF brews are like this though, because we can't use malt obviously, but I have seen plenty of GF recipes that don't even mention the use of yeast nutrient and only use 1 packet of dry yeast. I will definitely try yeast nutrient on my next batch, but would the weak boil affect it as well?

 

[Lurpinator]

For this recipe the weak boil would not affect fermentation - the suagrs are already ready to go, ready to be converted. The boil is not doing anything except dissolving them equally into the solution.

The boil really provides the opportunity for your hops to do their work and for you to boil off some off flavors some malts (like Pilsner) might produce, and of course it is reducing the amount of liquid from your mash to reach your SG. In your case the only thing that applies is the hops.

You dont really need protein to ferment - lots of wines have nothing but sugar in them (see EdWort's Apfelwein as an example, or look up any dandelion wine...). Your OG is not all that high, 1 packet of properly rehydrated S-04 should be fine, and two packets should be extra fine... what temperature are your fermenting at? Is your yeast fresh?

Thanks, I wasn't sure about the boil in GF brews. I pitched the yeast dry at about 70 degrees, and I got my yeast from my LHBS, so I assume it's fresh. My last batch (GF sorghum brew) had slow ferm problems as well and I used US-05 from the same LHBS, but they were restocked this time around. I'm fermenting at about 65 degrees in the basement (same location as first brew)

 

[Lurpinator]

Anybody have any ideas?

 

[Brew-Happy]

Lurpinator,

Do you have a way of testing the pH of the wort?

According to Briess, 10% solution of Tapioca syrup results in a pH of 5-6.

Does this seem to high to anyone else? Could this slow fermentation?

This is assuming your syrup is the same as Briess.

Here is the pdf Link

 

[Lurpinator]

Lurpinator,

Do you have a way of testing the pH of the wort?

According to Briess, 10% solution of Tapioca syrup results in a pH of 5-6.

Does this seem to high to anyone else? Could this slow fermentation?

This is assuming your syrup is the same as Briess.

Here is the pdf Link

My LHBS buys their sorghum and tapioca syrups from Briess, so those numbers apply to my brew as well. My dad has some pH strips for the hot tub, but I believe the pH numbers are very limited on those, and other than that I have no way of testing it. This is frustrating because it happened on my first brew, there has to be some explanation for it. If anybody has any other possibilities, that would be awesome. Thanks

 

[david_42]

I vote for yeast nutrient, as there is nothing in your recipe for them to use for growth and adaptation.

 

[Joe Camel]

You dont really need protein to ferment - lots of wines have nothing but sugar in them (see EdWort's Apfelwein as an example, or look up any dandelion wine...).

This is not true, all fermentations need a source of nitrogen for the yeast to use. You can either provide amino acids, peptides or tannins, as are present in wort, cider and wine must, or you should provide an artificial source to boost the content if it is lacking. The yeast can convert most sources into protein building blocks to grow and ferment.

Here is an interesting read on the matter from http://www.cider.org.uk/nitro.htm
that sums it up rather grossly.

In practice, cider apple juices contain much less nitrogen than grape juices or beer worts - typically five or ten times less. This has major implications for the conduct of cider making as compared to winemaking or brewing. A traditional British or French cider fermentation takes four or five months for completion, from November or December through to March or April. No modern winemaker or brewer would ever wait that long! As a result, it is now common practice for modern commercial cider makers to add extra nitrogen in the form of ammonium phosphate and thiamin. The purpose of these additions is to give the yeast enough to feed on to ensure a rapid fermentation - there is already sufficient carbohydrate in the form of juice sugar, but the yeast needs assimilable nitrogen (readily supplied by amino acids or ammonium salts) to make protein for its own growth.

Yeast also needs the nitrogen-containing vitamin thiamin (vitamin B1) which plays an essential role as a co-factor during fermentation particularly in the final enzymic conversion of pyruvate to ethanol. Both materials are in short supply in traditional apple juice - so much so that hanging a side of meat in a vat of cider whose fermentation had 'stuck' was once regarded as a normal procedure in English farmhouse cidermaking, because the meat provided both the amino acids and the vitamins which the juice was lacking. There are quaint stories of stuck ciders becoming reactivated after rats drowning in the vats - presumably the extra nitrogen from the corpses was sufficient to get the yeast going again!​

 

[Joe Camel]

All GF brews are like this though, because we can't use malt obviously, but I have seen plenty of GF recipes that don't even mention the use of yeast nutrient and only use 1 packet of dry yeast. I will definitely try yeast nutrient on my next batch, but would the weak boil affect it as well?

This is a silly question, but what do you mean by GF? I had thought this was something you were making for your girlfriend, but not I'm not so sure.

 

[mmb]

This is a silly question, but what do you mean by GF? I had thought this was something you were making for your girlfriend, but not I'm not so sure.

Gluten free.

For people allergic to gluten in wheat, barley, etc

 

[Lurpinator]

So, I went to the Briess website, and read up a little bit about the tapioca syrup, and it seems that the sorghum syrup is very much like barley extract with the enzymes it has and everything, but the tapioca lacks a lot of the same enzymes that are necessary to healthy fermentation. So, I should have used yeast nutrient from the start, so now I guess its yeast energizer that I need to get, so that healthy fermentation can happen. I guess thats all part of this GF experiment, so anyone wanting to brew GF, I would stick with sorghum if you can, or use yeast nutrient.