Brewer's Invert Sugar (Part II)

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chthon

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@peebee There is definitely a difference in mechanism, but the outcome depends. I found a nice link explaining the issue. Together with some other background information:

Code:
Yeast -> Invertase + sucrose -> Glucose
     \                      \-> Fructose
      \-> Maltase + maltose -> Glucose x 2

So, apparently, S. cerevisiae makes these two enzymes always, without problems.
However, what you apparently have is that depending upon the strain, glucose is normally preferred (apparently especially with wine yeasts). And the more alcohol is formed and nutrition is depleted, the less yeast wants to ferment fructose. This can lead to a stalled fermentation.

a) Making sure that there is enough nutrition will probably help make it easier to ferment the remaining fructose

b) There should be no difference between sucrose and invert syrup. The presence of fructose could be a problem (or not) in both cases

c) And then there is the issue of selective evolutionary pressure: beers that were brewed with invert syrup will probably have lead to yeasts that have less problems with sucrose and fructose than beers that were brewed with malt only

d) The real test to check for differences between beers is to compare one brewed with added sucrose, and one brewed with maltose syrup. Not glucose, because that distorts the equation: the enzyme action should be there.
 

peebee

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This second brew is being as tardy as the first. Only a little tardy, but probably another full three days to finish (I'm used to stronger brews only taking 2 - 2½ days). The first set off quick though the second is making up for lost time. I'll resist the temptation to declare the first's fast start is down to all that glucose (from the Invert), as it's just as likely the yeast starter. But the Whitbread yeast (Wyeast #1099) perhaps isn't the best with sugar, maybe the later yeasts (e.g. Wyeast #1098) may have been better in these cases?

@chthon: Missed the "winemak-in" link first off! Interesting stuff, but don't forget sugar, and the inclusion of fructose, will only be about ¼, or less, of the fermentables in beer wort with the rest made up of maltose and dextrin. There shouldn't be the same issues with nutrients and stuck ferments. I understand yeast's ability to ferment maltose came later in its evolution so the preference for fermenting sucrose before maltose remains. But the presence of fructose being a likely candidate for the "tardy" fermentations I'm experiencing is "comforting" (better than panicking thinking "aarg, what's going on"). Sugar in beer is all a new experience for me.

It worries me (slightly) that the strong "scent" of 1970s pubs (all that Watney's Red, etc. keg beers ... ignoring the fag smoke) when "kegging" the first attempt at 1898 Hancock XX (Ragus Invert) is significant?
 

marshbrewer

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Before anyone puts forward the claptrap that yeast must work harder to invert the sucrose (for which it requires invertase enzyme) this is a good illustration that next on the menu is the considerable proportion of maltose, also a di-saccharide for which it requires maltase enzyme: Brewers don't pre-convert maltose to be easier on the yeast!

Why is that 'claptrap'? Explain. You have a process that yeast cells must go through in one case and not in the other. Ergo, unless you can demonstrate that this process appears to be instantaneous, which it probably isn't given how enzymes work, then your own data substantiates the argument that there is a benefit to using invert verses non-invert in brewing, does it not (that benefit being time for fermentation to begin, which in a commercial sense is an economic benefit, and in the homebrew sense has value in reducing the time that wort is at its most susceptible to infection)? What ever is next in the pipeline for the yeast is irrelevant.
 

peebee

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Why is that 'claptrap'? Explain. ...
I did explain. In the rest of that post. And @chthon backed it up, together with an offsite link too. But, to reiterate:

Yeast cells are already geared up to produce invertase, both internally (within the cell) and externally (hence the Victorians would use yeast to "invert sugar"). The cell also produces "maltase", that might only be internally, I've not come across anything to support excretion of maltase? Note maltose is not "inverted", it is converted to two glucoses with the same optical rotation direction as maltose, so the optical rotation is not reversed (inverted); that needs creation of fructose.

So, yeast cells are not put to any additional stress creating invertase as they do it anyway. And if it was an undesirable stress, why don't brewer's "save the yeast" the effort of converting maltose?

I've pointed out that my fermentation may have gotten off to a quick start because of the glucose available from the start, but the sucrose version wasn't far behind (six hours) and quickly caught up (< 24 hours). I also pointed out that these observations are irrelevant given the yeast starters are quite capable of showing a similar delay despite being prepared to produce similar quantities of cells. One example is not enough to draw valid conclusions from. For most homebrewers twelve hours to begin fermentation is pretty slick anyway. Don't care about commercially: The Victorians claimed sucrose damaged the yeast in successive generations so "invert sugar" was essential ("invert sugar" production was also a cheap shortcut for sugar refining in some countries, like the UK). The 1960s saw the beginning of the end of "invert sugar" as breweries switched to cheap sucrose syrups which probably better answers that question.

Also ... I haven't personally declared "inverting sugar" as a wholly useless process. That's why I'm doing these comparisons! But at this time, for me, things are not going well for all the time spent (wasted?) "inverting" sucrose. I've already found caramelising invert sugar (fructose) for colour to be utter claptrap along with taking steps to create "Maillard products"; increasing I'm finding the stuff supporting the need to make "invert sugar" to be "claptrap" too!
 

peebee

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Unless we are concerned with lag times ;)
In which case look to your "yeast starter" regime. Or use glucose and avoid the fructose in Invert Sugar which could be causing its own problems*?

( * see above; Brewer's Invert Sugar (Part II)).



[EDIT: Just checked my "records" ... both "XX" beers started at (remarkably!) the same - 1.039 at 18.6°C - and after 47.5 hours recorded 1.019 at 20.1°C (Ragus Invert) and 1.021 at 20.2°C (emulated Ragus, using sucrose). Recorded from Tilt Pro device (not infallible!). Not much sign of excessive "lag" there.]
 
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peebee

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Ok, I'll bow out as I don't want to turn your thread into an argument. I do worry that you are fitting the results around a theory rather than the other way around.
Hey! You can't "bow out" and then take a passing shot. That's cheating!

Anyway: It's not a "theory", it's at best a "conjecture". And I'm in insufferable right-and-proper mode!

Your memory is short, and this thread is long. At the beginning I was all for Invert Sugar (but cheating and using Lyle's Golden Syrup as a shortcut); even colouring it by heating it up (I bought not one, but two "Instantpots" to help do this). This entire thread has not been me fitting the results to my ideas, more me adapting my ideas to fit the results (with a bit of help from Google searches and some fellow forumites/homebrewers). I know I'll be forgotten soon enough, and homebrewers will return to the insanity of acid inverting, caramelising sugars, and adjusting pH to best enhance "Maillard reactions". But for the time being a number of forumites will be happy to be told that to be historically correct they don't have to spend hours over pots of boiling sugar solutions with pH papers at hand, but instead spend a few minutes looking in their local supermarkets for ingredients.
 

scrap iron

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I have been following this thread with interest and enjoying the back and forth of the different comments. While I am no authority on British beers I love Bitters and being of English ancestry, mostly anyway, would love to do them justice in my attempts. I'm sure you might be aware of this write up but if not here it is.
Shut up about Barclay Perkins: Refined sugar vs invert sugar
Some of the comments following might be of interest.
 

peebee

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I have been following this thread ...
Haven't seen that thread on RP's site. Looks interesting.

I don't think you are mixing me up with the "Invert Sugar deniers"? But I bet some here are making that misunderstanding. I do not think highly refined sugar makes an adequate replacement for invert sugars. I'm just campaigning against those that are trying to make "Invert Sugar" unattainable to those that want it. It is attainable. It's some of the ludicrous schemes to make Invert Sugars that are wholly inaccurate and should be unattainable!

"Invert Sugar" Emulations

Remember though, this banter is a break from some trials I'm currently working on that won't produce results for two or three weeks yet.
 

scrap iron

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Thanks for the reply and I'm looking forward to your results. I have a question about a base added after inversion is complete. I have not done this and was curious what is the reason for it. I have made a few inverts but have not tried to make them darker with heat. I have instead tried different raw sugars available in the US, turbinado, and a darker one demerara. Sorry if this off topic but I'm still learning on this subject.
 

peebee

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... I have a question about a base added after inversion is complete. I have not done this and was curious what is the reason for it. I have made a few inverts but have not tried to make them darker with heat. I have instead tried different raw sugars available in the US, turbinado, and a darker one demerara. Sorry if this off topic but I'm still learning on this subject.
I believe ... commercially they used fairly strong acids to perform inversion. Ragus decrease the pH to somewhere 'tween pH1 and 2. The temperature doesn't go higher than 70-80°C. Inversion is complete within minutes. (Taken from their own published descriptions). if it were left at such a low pH the sugar would be destroyed! So, bases are added to get the pH back up again (to about pH5-6). The sugar syrup isn't made alkaline (pH7+) as that will destroy sugar too. Because inverting done at home is done at modest acidities over much longer time periods there is probably no real need to neutralise the acid used.

You can make invert sugar darker by heating it above 110°C (the caramelisation temperature for fructose; one of the products of inversion). But this is not normal practice. Caramelisation also destroys sugar. Some caramelisation does occur during (old style) sugar refinement (along with some Maillard reactions) and is the reason "molasses" is so dark and flavoursome (fresh sugar cane juice is about the colour you'd expect from squeezing grass). Invert Sugars are made from sugars at various stages of refinement and gain their colour and flavors from the molasses components they contain.

The various grades of refined sugar were given a number: No.1 through to the roughest and least refined No.4. These numbers have transferred over time to mean colour when referring to invert sugar. And modern refining methods means No.4 is probably the most tasty rather than the "roughest". No.1 is no longer subject to techniques to remove tastes and colour as once was necessary (passing over active charcoal - burnt bones that is!). Ragus now refer to their invert sugars as Light, Medium and Dark. Don't get carried away by the colours, some 15% (of fermentables) of "Dark" (No.3) as the only source of colour other than pale malt will only make a beer of about darkish amber (not brown).
 

chthon

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I have been following this thread with interest and enjoying the back and forth of the different comments. While I am no authority on British beers I love Bitters and being of English ancestry, mostly anyway, would love to do them justice in my attempts. I'm sure you might be aware of this write up but if not here it is.
Shut up about Barclay Perkins: Refined sugar vs invert sugar
Some of the comments following might be of interest.
Very interesting. From a practical point of view for the homebrewer it would then be: buy unrefined or lightly refined cane sugar (depending on what you want to achieve), add citric acid or tartaric acid, keep this in your oven at 80° C. Sodiumbicarbonate for stopping the inversion is optional.

I have a pale ale fermenting but I haven't added the sugar yet, so I could try this experiment before racking to my secondary vessel, where I normally add the sugar.

Edit: of course this is only a partial test, more out of curiosity. To be complete, one would almost need to do the following tests with the same recipe (malts and hops)
  • Use white crystalline sugar
  • Use inverted white sugar
  • Use raw cane sugar
  • Use inverted raw cane sugar
    • Inverted with citric acid or cream of tartar
    • Inverted with sulphuric acid or hydrogen chloride, then neutralized
 
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peebee

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The second brew (emulated Ragus Invert) has completed primary fermentation and is awaiting kegging (couple of days). Meanwhile, I've hacked the graphs from the Tilt Pro output to provide side-by-side comparison:

Capture-ONEii.JPG
Ragus Invert
Capture-TWO.JPG
Emulated "Invert"

The first (Ragus Invert) has been hacked to appear the same scale hence the lines look a bit blurred (the dates are wrong too!).

Pretty similar though. But it does show the Ragus Invert brew got off to a quicker start (but this is not enough data to properly conclude why). Temperature is recorded from the floating Tilt hydrometer, not the probe in the Grainfather that controls the heating/cooling, hence it appears a bit choppy. Careful what you read into gravity readings during fermentation as the yeast cap messes up the readings (interesting how with 24 hours to go, the gravity reading jumps up; this will be yeast build up on the Tilt sliding off as the Tilt swings into a more upright position). The random "hiccups" in gravity readings are nothing like as bad as would be experienced with the smaller "non-Pro" Tilt hydrometer.

Next the taste comparison, but that may not be for one to three weeks.
 

peebee

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The various grades of refined sugar were given a number: No.1 through to the roughest and least refined No.4. ...
That didn't come across quite as I intended: I have no evidence that No.1-4 ever referred to sugars other than invert sugar. But for invert sugar what the numbers referred to would be the refined state of the source sugars. Later it referred to colour, but the two are closely linked in this case.

Modern sugar refining means we probably can't experience the naked "rawness" of No.4 Invert. Even today Americans may find the idea of using "Blackstrap" molasses (about the rawest British sugar product we can buy) pretty unsavoury as "Blackstrap" still equals "pig food" over there, whereas we Brits can pop down to the Supermarket and buy it. "Black treacle" is for more "refined tastes" than uncouth "Blackstrap" but tastes the same to me.
 

peebee

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Can Fructose be used instead of Candi sugar?
Na. Check @chthon's posts above. Fructose, and anything containing it or causing it to be created like Invert Sugar (half-and-half, ...ish, glucose and fructose) and sucrose (yeast splits sucrose into glucose and fructose), might even have a (small) negative impact on fermentation. Don't let his posts on fructose panic you though! I think the concerns are aimed more towards winemakers as beer brewing relies chiefly on maltose to fuel fermentation.

Although I warn against drawing conclusions from only one or two samples, both of those "test" brews three posts above (#76) had tardy fermentations (fructose?) and finished a half to a full day later than I expected - enough to cause me concern at the time (I'm not used to brewing with sugar, and this was the opposite to what I expected). They both finished in three days though!

Interesting that the first of those "tests" contained glucose (from Invert Sugar), the easiest sugar for yeast to ferment, which might be responsible for a very quick start (six hours). I keep an eye on that to see if it's repeatable. The advantage (fast start) was lost in the next few hours.


"Candi Sugar" seems to be some homebrewing marketing nonsense (even "Candy" is spelt wrong!). Historically the Belgians used syrups that were most likely identical to the Invert Sugars the Brits were using. But like the Brits, they were also messing about with a multitude of different sugars. If anything, use Ron Pattinson's stance and clump different sugars listed for beers as Invert Sugars (my emulations hopefully!). I'd use Golden Granulated/Caster for anything just specifying "white sugar" but that's only because I'm a "la-de-da" ponce and think "white sugar" is "common".


Those "tests" are ready for sampling now, so expect updates soon after the weekend!
 

chthon

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I am busy reading some books from Brewers' Publications, and I came across the notion (can't find which one currently, could be "Simple Homebrewing by Denny Conn and Drew Beechum), that candy sugar derives its name from the fact that it were the leftovers from candy confectioners that were sold to the breweries.
 

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