Home Made Ice Cream (2015– )

[paulraphael]

I just wrote a long post about ice cream stabilizers, including information on customizing your own blends. This is pretty heavy going but I hope helpful for anyone who's been struggling with the topic. There's a lot of information here that you won't find elsewhere.

[sweettreateater]

On 5/30/2016 at 0:11 AM, JoNorvelleWalker said:

I've been successfully using the PHMB for over a year now, as I recall. 

 

I remember you also had a lot of success using Ruben's method. Are you using the PHMB to utilize same basic theory? (ie, 30-60 minutes at 162 degrees, etc)

 

Since I also like to play with chocolate, I'm quite interested in this gizmo. However, I don't have the space for a KA mixer so I would likely get the standalone version. Since I wouldn't have the mixer itself, I guess I'd still be standing there stirring but at least I wouldn't have to worry about the temperature.

 

Have you found that the temperature remains consistent, even if it differs from what reads on the display?

[sweettreateater]

6 hours ago, paulraphael said:

I just wrote a long post about ice cream stabilizers,

 

Looking forward to this one. I have frequent, animated, high-volume discussions about stabilizers with my girlfriend who refuses to eat ice cream that contains them. I like to point out that the unfortunately named guar gum is no less natural than her precious kale, yet she refuses to yield to my logic. So I just trick her. My ice cream has no labels on it.

[JoNorvelleWalker]

7 hours ago, cwfenn said:

Been doing custards the traditional way-How long did it take to get the custard to temperature in the PHMB?

 

It took 30 minutes from refrigerator cold to reach 143 deg F.  Unfortunately I did not record enough data points to answer the question.  Reading eGullet, even sober, does that to one.

 

@sweettreateater I've gratefully been using Ruben's method since I first tried it, although my mix is higher in butterfat and lower in sugar than Ruben's recipes.

[JoNorvelleWalker]

34 minutes ago, sweettreateater said:

 

I remember you also had a lot of success using Ruben's method. Are you using the PHMB to utilize same basic theory? (ie, 30-60 minutes at 162 degrees, etc)

 

Since I also like to play with chocolate, I'm quite interested in this gizmo. However, I don't have the space for a KA mixer so I would likely get the standalone version. Since I wouldn't have the mixer itself, I guess I'd still be standing there stirring but at least I wouldn't have to worry about the temperature.

 

Have you found that the temperature remains consistent, even if it differs from what reads on the display?

 

Sorry, I missed some of this question when I last replied...

 

As I recall at least one eG chocolate person reported problems with the PHMB.  I have never tried the PHMB for tempering chocolate so I cannot comment.  Kerry Beal makes a chocolate tempering machine and that is what I would look to if chocolate making were my thing...though it costs rather more than the PHMB and I'm not sure how great it is for making ice cream.

 

If the lid is on, the PHMB actual temperature approaches the set temperature asymptotically.  See my experiments last year.  With the lid off and the contents being stirred, the PHMB will not reach close to setpoint, but will hold a constant temperature.  I have found a setpoint of 198 deg F. gives an actual temperature of 162 deg F.  Note that this probably depends somewhat on the speed at which you mix.  Once you get the parameters worked out I am convinced the results are reproducible.

 

[JoNorvelleWalker]

Having thought about this some more, I would not recommend purchasing the PHMB without a mixer for making ice cream.  But as a slow cooker, quite possibly, yes.  For ice cream you just don't save enough effort.  Invest in a Thermapen Mk4 or learn to read a thermometer upside down while you stir the ice cream mix on the stove.

 

But with a mixer and PHMB you can just set a timer and walk away, while you read eGullet or paint your nails.

 

If KitchenAid doesn't float your boat, Kenwood makes what looks like a similar product.  Namely an induction heated mixing bowl on a stand mixer.

 

 

[JoNorvelleWalker]

Ice cream is so good.

[paulraphael]

I don't know why more people don't use an immersion circulator for ice cream. Precise, repeatable, and if you don't already have one, you need one!

 

I haven't made ice cream any other way since I've bought mine. 

 

A Thermomix looks like it would d a good job too, but I've never used one (they don't seem so common in the U.S.). And a lab hotplate with magnetic stirrer and thermocouple should be great, but those are expensive compared with the more conventional options.

[JoNorvelleWalker]

16 hours ago, paulraphael said:

I don't know why more people don't use an immersion circulator for ice cream. Precise, repeatable, and if you don't already have one, you need one!

 

No evaporation if you cook sous vide.  And, yes, I've tried.  Besides it is a pain or a mess (depending on one's skill and equipment) to vacuum seal a bag of ice cream mix.

 

When the Anova first came out I asked Anova Jeff about the possibility of a lab-like circulator that I could use to heat a vessel such as a KitchenAid bowl.  Turns out someone else has a patent on this method.

 

The induction heated PHMB is supposedly (from memory) good to one degree which while poor by Anova standards is more than OK for most of my ice cream cookery.

 

Your mileage may vary.

 

 

[Jim D.]

On 6/1/2016 at 0:02 AM, JoNorvelleWalker said:

 

Kerry Beal makes a chocolate tempering machine and that is what I would look to if chocolate making were my thing...though it costs rather more than the PHMB and I'm not sure how great it is for making ice cream.

 

Just to correct the record:  Kerry Beal's EZtemper machine does not directly temper chocolate (or make ice cream).  The user places solid cocoa butter in it, and the machine creates a semi-melted product (called "cocoa butter silk") and holds it at a set temperature practically forever.  The silk can be used to temper chocolate quickly and with less mess than when using small already-tempered pieces of chocolate and has other uses, such as tempering/crystallizing gianduja, meltaways, and ganaches.  It speeds up the production of chocolates quite noticeably and especially makes the crystallization of slabbed ganaches faster and more reliable.

[paulraphael]

It just seems to me that evaporation is a bug and not a feature. I don’t see how it’s possible without elaborate measures to simultaneously control evaporation and the the degree of cooking.

 

The rate of evaporation will vary not just with temperature, but with the size and shape of the vessel, the quantity of mix, the rate and type of stirring, and the ambient temperature and humidity.

 

So if you’re cooking to a set time/temperature, the evaporation will vary. If you cook to a set evaporation (by stopping and measuring frequently?) the cooking time will vary. 

 

If you want to increase milk solids, add nonfat dry milk. There are zero downsides. Use a good brand and it will be pure skim milk, spray-dried at a lower and better controlled temperature than what you’ll ever manage in the kitchen. There’s a reason that most of the best pastry chefs do it this way.

 

If I didn’t do sous-vide, my first choice would probably be a lab hotplate, with a pan lid drilled for the thermocouple probe.

 

Edited to add: 1° accuracy should be more than good enough for ice cream. Is there a way to cover the KA heated bowl while it's working?

Edited June 2, 2016 by paulraphael (log)

[JoNorvelleWalker]

Hobart type planetary mixers like the KitchenAid are not easy to cover.  The only semi practical way I can think of is to purchase the hand guard attachment and cover the openings with foil.  If you mean is there a way to cover the bowl while it's heating but not being mixed, just put the lid on it.

 

Though if you cover the bowl you don't get evaporation...which I want.  I am aware there are a lot of variables, but as I have said before, once the process is worked out the results should be quite consistent.  Except for ambient temperature and humidity (and atmospheric pressure) the mix formulation, bowl size, temperature, RPM, and mixing time are all controllable or fixed.

 

 

Edit:  plastic wrap would probably be better and easier than foil.

 

Edited June 2, 2016 by JoNorvelleWalker
afterthought (log)

[cwfenn]

On May 31, 2016 at 4:51 PM, paulraphael said:

I just wrote a long post about ice cream stabilizers, including information on customizing your own blends. This is pretty heavy going but I hope helpful for anyone who's been struggling with the topic. There's a lot of information here that you won't find elsewhere.

Many thanks-I've been looking into different stabilizers and this looks good.

[sweettreateater]

On 6/1/2016 at 8:24 PM, JoNorvelleWalker said:

I've gratefully been using Ruben's method since I first tried it, although my mix is higher in butterfat and lower in sugar than Ruben's recipes.

 

I've also had really good success with Ruben's method. This week, I tried a comparison test where I used the exact same proportions of ingredients but just dumped everything in the pot, brought it to 162, let it simmer for about 5 minutes, and then put in an ice bath. The result was OK but definitely did not have that unique creaminess.

 

I wonder what are the biggest contributors? Is it the reversible protein unfolding and denaturing? Or is it mainly just due to evaporating so much water out of the base, which is ultimately what would contributing to any iciness?

 

Also, I realized recently that I've been setting up all my percentages BEFORE reducing it. Then I realized that since the actual amount of base that gets churned is 13% lighter, (since I've removed about 13% of water from the base with evaporation), it also means that my ingredient percentages all increase quite a bit. I noticed today that Ruben mentions this on his site (ie, arrive at the proper mix composition AFTER heating) but I didn't see it before.

 

The ice creams have been pretty soft at 5 degrees out of the freezer (though I kind of like that consistency), and now I think that's because I have a higher percentage of sugar in the base than my pre-reduction numbers indicated which suppresses the freezing point...

 

[paulraphael]

52 minutes ago, sweettreateater said:

I wonder what are the biggest contributors? Is it the reversible protein unfolding and denaturing? Or is it mainly just due to evaporating so much water out of the base, which is ultimately what would contributing to any iciness?

 

 

100% the latter. By evaporating water, you're increasing both the nonfat solids and the fat. 

 

There is possibly some effect from denaturing the whey proteins, but I don't believe you're going to notice it in these recipes. Mainly because they are very heavy on egg custard, so they have more than adequate added emulsifiers already. 

 

There is some research suggesting that with prolonged cooking, whey proteins can aggregate with casein proteins, forming a hydrocolloid with thickening / stabilizing ability. But this seems difficult to accomplish. Even Jeni Britton-Bauer of Jeni's Splendid—who's a pioneer in using milk proteins as emulsifiers in egg-free ice cream—adds starch as a stabilizer.

 

If you want to increase the fat and nonfat solids of an ice cream, evaporation is a way to do it. But you'll have an easier time and get more consistent results by just using a higher percentage of cream and dry milk. 

 

In my experiments, cooking milk proteins to varying degrees in a formula that's lower in fat and much lower in egg yolk than Ruben's formulas, I find the effect to be extremely subtle. It's likely that you will only see any effect if you're using milk that's been pasteurized at low temperatures (and dry milk that's been spray-dried at low temperatures). 

 

Edited to add: 

There's something I'm leaving out. The differences aren't 100% evaporation; some of the difference is from adequately thickening the egg custard. Contrary to what used to be taught in cooking school, custard consistency is a factor of not just concentration and temperature, but also time. An egg custard brought to 162F for two minutes will thicken very little compared with one held at that temperature for 15 minutes. Dr. Cesar Vega confirmed this in tests done with a rheometer.

Edited June 4, 2016 by paulraphael (log)

[JoNorvelleWalker]

Yesterday I spun another batch of ice cream, the second half of same mix as a couple days ago.  It came out of the Cuisinart at -5.5 deg C.  After 24 hours in the freezer the ice cream was just too soft and the texture was OK but not great...well OK, not really OK.  The texture had been better right out of the Cuisinart.  I measured the ice cream temperature from the freezer at -8.4 deg C.  Something's not right.  This temperature seems far too high.

 

And then I measured the temperature again with a different thermometer but the same result.

 

The previous batch was soft too, but not this soft.  And after the last batch I defrosted the freezer to try to get the temperature lower.  (And then waited a day for the freezer to get back down to temperature before spinning the ice cream.)

 

When I last measured my freezer temperature it was -21.1 deg C.  But this was in 2013.  I have a bottle of technical alcohol chilling now to take a reading.  Maybe I should just drink it.

[Jim D.]

57 minutes ago, JoNorvelleWalker said:

 I have a bottle of technical alcohol chilling now to take a reading.  Maybe I should just drink it.

 

That should really make a zombie with a lasting effect!

[JoNorvelleWalker]

At the moment the ice cream is down to -11 something deg C.  Texture is improved.  Meanwhile the bottle of alcohol measures -16.3 deg C.  Still not good enough.

 

We shall see what the morrow brings.

[paulraphael]

Freezer problems are a drag. The freezer in my old place could be set to -5F / -20C and hold it comfortably. My current freezer struggles to maintain -1F / -18C, and it makes a big difference. Even with all the improvements I've made in my formula, it's hard to get the ice cream as smooth as it was with the better freezer.

Edited June 5, 2016 by paulraphael (log)

[JoNorvelleWalker]

I did measurements over almost 24 hours.  The freezer varies between -10 and -16 deg C.  I can drink the bottle now.

 

But at least the ice cream is harder than when I started.

[JoNorvelleWalker]

I had some of the ice cream just now.  (The same batch I have been discussing.)  Hardness was acceptable and texture was still lovely.  So I stuck a thermometer in it:  -11.8 deg C. again.  What a difference from -8.4 deg C the other day.  Difficult for me to comprehend the difference in quality from a delta of a (very) few degrees.

 

But I'm concerned that after twenty four hours in the freezer the ice cream had only chilled down less than three degrees.  That's just not right and it almost defeats all my love and care.  I'd be ashamed to serve -8.4 deg C. ice cream to my grandkids...and I'd never hear the end of it.

 

As an (in)sanity check I just now pulled the bottle of technical alcohol and took a reading:  -19.0 deg C.  No zombies were harmed in this experiment.  The freezer is acting a little more like its old self.  Maybe a freezer takes more than a few days to cool down after defrosting?  So much I do not know about freezer technology.

 

But this has me thinking, what is a reasonable freezer temperature for ice cream?  I know I'd prefer the serving temperature of my ice cream colder than -11.8 deg C.  I understand the standard storage temperature for ice cream, at least in the US, is -28.9 deg C.  But I'm typically holding ice cream for only a few days at most.  Not weeks.  On the other hand, the quicker the ice cream cools to storage temperature, the smaller the ice crystals.  And all else being equal, the colder the initial temperature of the freezer, the faster the ice cream will cool.

 

This of more than theoretic interest as I find myself again window shopping for freezers I can ill afford.  I think I can rule out -20 deg C. freezers as not cold enough.  Is -25 sufficient?  -30?  -45?

 

 

[paulraphael]

I'll bet you hit it on the head, and it just took the freezer a long time to recover from defrosting. It can take a fridge / freezer 24 hours just to stabilize after changing the thermostat setting. Not sure why it takes so long.

 

Ideal freezer temperature is a tricky issue, since at home we use the same freezer for hardening, for storage, and for serving.

 

According to Dr. Cesar Vega, the ideal hardening cabinet is -33°C / -27°F. Most actual hardening cabinets are -40, and conventional wisdom is that the colder the better, but Vega says (somewhere) that if you freeze ice cream too cold, the water turns to water glass, rather than crystalline ice, and this can lead to large crystals forming when it warms up. But most of us don't have to face this problem.

 

For storage, he says typical ice creams are completely stable at -25°C / -13°F or below. Ice crystals won't grow, because all the water is solid. 

 

For serving, standard practice is -14 to -12°C /  6 to 10° F. Ice cream shop scooping cabinets are probably somewhere around there. Too warm for everything else you use a freezer for.

 

In my experience, -20C / -5°F worked well for everything. It was the coldest my old freezer would go, so I couldn't compare lower temps. It hardened the ice cream quickly and gave great texture, and the ice cream only took a few minutes to soften after you pulled it out. The only drawback I found was energy use. It wasn't the newest of fridges and you could tell it was cycling on a lot. 

 

Edited to add

I've looked into the idea that a hardening cabinet shouldn't be colder than 33°, and don't think there's anything to back it up. In order for water to form a glass (amorphous ice) it has to freeze to a temperature lower than this in milliseconds. Which is not going to happen when you put a pint container into the freezer. This is something you might think about when making liquid nitrogen ice cream (and it's the whole idea behind dippin' dots). 

 

Probably the conventional wisdom is right, and colder is better in a blast freezer.

Edited June 18, 2016 by paulraphael (log)

[paulraphael]

I just wrote a long post on Ice Cream Emulsifiers. This will mostly be of interest if you wish to make egg-free ice creams, or if you really want get your nerd on.

 

 

[sweettreateater]

The information in underbelly is great!

 

I particularly liked the 'Discussion' section in Basic Ice Cream Examples, where you showed how a change in the recipe can result in unexpected deficiencies, but then how to counter that effect by changing other parts of the formulation. It really demonstrates the crucial balancing act that ice cream-making is! And it really helps make clear what each part of the formulation does.

 

One thing that I would personally really like to see is an entire posting on Solids: how to calculate them from your ingredient list, how to add them in when needed, how to counter them when they come in too high. I find the whole Solids component the trickiest part to understand well. It was covered in How To Build a Recipe but I wouldn't mind seeing more, especially how to manipulate the percentage.

 

For instance, how would you get enough solids if you were making a watermelon ice cream? You need a ton of watermelon juice to get enough flavor (because it's a relatively non-intense juice next to say, lemon), but then how do you maintain a high enough solid percentage without diluting the flavor?

[JoNorvelleWalker]

1 hour ago, sweettreateater said:

The information in underbelly is great!

 

I particularly liked the 'Discussion' section in Basic Ice Cream Examples, where you showed how a change in the recipe can result in unexpected deficiencies, but then how to counter that effect by changing other parts of the formulation. It really demonstrates the crucial balancing act that ice cream-making is! And it really helps make clear what each part of the formulation does.

 

One thing that I would personally really like to see is an entire posting on Solids: how to calculate them from your ingredient list, how to add them in when needed, how to counter them when they come in too high. I find the whole Solids component the trickiest part to understand well. It was covered in How To Build a Recipe but I wouldn't mind seeing more, especially how to manipulate the percentage.

 

For instance, how would you get enough solids if you were making a watermelon ice cream? You need a ton of watermelon juice to get enough flavor (because it's a relatively non-intense juice next to say, lemon), but then how do you maintain a high enough solid percentage without diluting the flavor?

 

You might want to take a look at the ice cream geek calculator:

 

http://www.icecreamgeek.com/?page_id=817